Haiti — A group of gunmen wielding assault weapons assassinated Haitian President Jovenel Moïse and wounded his wife at their home in the hills overlooking Port-au-Prince early Wednesday, plunging the Western Hemisphere’s poorest nation deeper into a destabilizing crisis.

The attack by assailants that Haitian authorities described as “commandos” comes amid months of escalating political instability and gang violence that have critically eroded the rule of law in the Caribbean nation of 11 million. Moïse, 53, dissolved parliament in January 2020 and ruled by decree as opponents and protesters demanded that he step down. Armed gangs with unclear allegiances have seized control of growing portions of the country, terrorizing the population with kidnappings, rapes and killings.

Léon Charles, head of the Haitian National Police, told reporters late Wednesday that his forces had detained two of the assailants and killed four others, liberating three police officers being held hostage in the process.

He said police had been engaging the attackers since the early hours of Wednesday, after blocking roads they had intended to use to escape the city.

“As I am talking to you, the fight is ongoing with the assailants,” Charles said. “We will hunt them. They can be killed in an exchange of bullets, or arrested.”

Haitian authorities did not identify the assailants killed or in custody. But Communications Minister Pradel Henriquez said the men were “foreigners.”

Haitian authorities, eyewitnesses and videos that circulated on social media indicated the assailants were speaking Spanish and English in the Creole- and French-speaking country, and apparently claimed to be with the U.S. Drug Enforcement Administration to sow confusion during the audacious operation. There were no immediate reports of injuries among the president’s security detail, prompting questions about why the attackers apparently met little resistance.

Interim prime minister Claude Joseph, who said he was now the head of Haiti’s government, denounced the “odious, inhuman and barbaric” attack. Haiti’s Ambassador to the United States, Bocchit Edmond, said the government had requested assistance from the United States in boosting its police and armed forces. He said a manhunt was underway to chase down what he called “well-trained professional killers, commandos.”

No group immediately claimed responsibility for the attack.

Joseph announced a nationwide state of siege with security under the control of the country’s armed forces and police. He appealed to Haitians to remain calm, and called on “all the forces of the nation to accompany us in this battle, in the continuity of the state because democracy and the republic must win.”

President Biden condemned what he called the “heinous act.”

“We stand ready to assist as we continue to work for a safe and secure Haiti,” Biden said in a statement. Speaking to reporters at the White House, he called the attack “very worrisome” and said “we need a lot more information.”

Neighbors heard the outbreak of heavy machine-gun fire shortly after 1 a.m., coming in spurts of 10 to 15 minutes for more than an hour.

“The weapons I heard I had never heard in Haiti before,” said Ralph Chevry, a board member of the Haiti Center for Socio Economic Policy in Port-au-Prince, the capital. He lives just over a mile from the president’s residence and said he heard the fighting clearly.

Chevry said neighbors heard the black-clad assailants speaking in Spanish. In audio recordings purportedly made during the attack, the authenticity of which could not be confirmed by The Washington Post, at least one man with an American accent speaks in English and claims to be from the DEA.

“DEA operation. Everybody stand down,” the man says in what sounds like a Southern accent.

U.S. officials strongly denied the claim. The Biden administration has supported Moïse.

“It sounded like a ruse, a tactic,” Chevry said.

In a grainy video, eyewitnesses describe at least some of the attackers as “White,” and say they see some of them walking by Haitian police, who they say appear to be standing down.

“Do you see these guys disarming Jovenel’s guys?” one man asks. “The president is gone.”

“I am convinced they were foreigners, though they might have been helped by some nationals, for logistics, for cars, and how they arranged to arrive at the president’s home,” said Edmond, the Haitian ambassador. “They needed assistance. They were screaming ‘DEA operation,’ but we know it was fake. We know they were not DEA agents.”

State Department spokesman Ned Price, asked Wednesday about reports of foreign mercenaries in the operation, said, “We don’t have clear answers at this time. What we do know and what we’ve said is that Haitian authorities are investigating, and we stand ready to offer assistance to that investigation.”

“It is still the view of the United States that elections this year should proceed,” Price told reporters. “We have urged the Haitian government and stakeholders repeatedly to reach a political accord to ensure legislative and presidential elections take place this year.”

Edmond said first lady Martine Moïse remained in critical but stable condition. A plane carried her Wednesday afternoon to Fort Lauderdale, Fla., for care in the United States. Edmond said the Haitian government had been in contact with the State Department and the White House.

In the wake of the assault, the streets of the capital were eerily calm on Wednesday, with little police presence beyond the presidential residence, even as a sense of fear lingered.

“The news has shaken us,” said Clifordson Désir, an electrician in Port-au-Prince. “If the first man of the country can be killed like that, the population is not safe.”

Later Wednesday, gunshots rang out in the Pétion-Ville suburb of Port-au-Prince. A senior Haitian official said police had discovered a safe house being used by suspected assailants. The official also said that Jean Rebel Dorcenat, who served as Moises’ liaison to the powerful street gangs, was detained for questioning near the border with the Dominican Republic.

Joseph requested an emergency meeting of the U.N. Security Council. U.N. diplomats said that a closed Security Council session on Haiti would be held immediately after a meeting on Africa scheduled for Thursday morning.

The state of siege grants broad powers to the government for 15 days to search homes and property, restrict the right to gather and control the roads, among other measures.

Compounding the crisis was a lack of clarity over who has the authority to lead the country. Joseph, the foreign minister, was supposed to step down as interim prime minister following Moïse’s appointment Monday of neurosurgeon Ariel Henry to be Haiti’s new prime minister. Edmond called Joseph the nation’s temporary ruler, at a time when the island appears to be tipping toward chaos.

Gang violence and the coronavirus outbreak are both worsening. A shooting rampage in the streets of Port-au-Prince last week left at least 15 people dead. At least 278 Haitians have been killed this year in attacks that have led some citizens to flee the capital, traveling by boat and plane to avoid dangerous, gang-controlled roads.

“The president was assassinated in his own house,” said Pierre Espérance, director of Haiti’s National Human Rights Defense Network. “Do you see our situation? It is terrible! We are not safe.”

A leading foreign investor in Haiti, who spoke on the condition of anonymity to be candid, said a consensus among business leaders was that the operation was too sophisticated to have been carried out by the armed gangs who have wrested control of parts of the capital and country.

The investor noted that Haiti has become an increasingly important transit point for cocaine and illicit cash, and that cartels and drug runners from Colombia, Venezuela and Ecuador, some of whom appeared to have been at odds with Moïse and people close to him, had gained a foothold in the country.

“This was too organized for the gangs,” the investor said.

The U.S. Embassy in Port-au-Prince said it was restricting U.S. citizen staff to the embassy compound until further notice. The embassy said it would shut down and recommended against unnecessary travel in the area. Haiti’s airports closed to commercial traffic and the Dominican Republic announced it was closing the land border between the two countries.

The power vacuum in Haiti, observers said, could create more space for gangs to seize additional territory, as one of the few countries without coronavirus vaccines struggles to contain a growing outbreak. Deteriorating conditions could add to the already growing number of Haitians fleeing the country.

“The spiraling political crisis and the high levels of violence we’re seeing, with the president’s killing being the most blatant example, will likely lead to a greater exodus,” said Tamara Taraciuk, deputy director for the Americas at Human Rights Watch.

Jovenel Moïse was the 58th president of Haiti. Born into a middle-class family in 1968, he was a businessman who ran a banana export company, which earned him the moniker “the Banana Man.”

He was handpicked by former president Michel Martelly, who resigned in 2016, and came to power a year later, the start of a tenure that was controversial from the beginning. In 2017, he was accused by Haitian authorities of money laundering through an account he held with his wife, the business executive Martine Marie Étienne Moïse. He denied the charges.

More recently, human rights leaders accused Moïse of maintaining links to violent street gangs, bands of which have been seen by witnesses riding in the armored vehicles used by the national police and special security forces. He denied ties to the gangs, which he’d described as Haiti’s “own demons.”

Moïse was elected to a five-year presidential term in 2016, but a dispute over the election results delayed the start of his term by a year. He insisted the delay entitled him to remain president for an additional year. His opponents disagreed, and in February, when they say his term ended, one faction declared Supreme Court Judge Joseph Mécène Jean-Louis as interim president. Moïse condemned the move as a coup attempt, and 23 opponents were arrested.

The dispute sparked a constitutional crisis in the Western Hemisphere’s poorest nation. Fighting between rival gangs and police in the capital in recent weeks has displaced thousands of people, according to the United Nations.

“The unprecedented level of violence and subsequent displacements is creating a host of secondary issues, such as the disruption of community-level social functioning, family separation, increased financial burdens on host families, forced school closures, loss of livelihoods and a general fear among the affected populations,” the U.N. Office for the Coordination of Humanitarian Affairs reported last month. Prices for basic necessities are surging.

Anti-corruption activist Emmanuela Douyon said she was in mourning not just for a man, but for Haiti.

“Never would I have imagined that the head of the country would be assassinated,” she said. “If he can be assassinated in his home who is safe? Whose life matters in this country? How are we supposed to keep going and keep burying our loved ones?”

Moïse was seeking to change Haiti’s constitution, adding provisions that critics warned could be the building blocks of authoritarian rule. They were also opposed by the Biden administration. Under Moïse’s plan, a referendum on the constitution was to be held on Sept. 26, along with previously scheduled presidential and legislative elections.

But if he had enemies in the opposition, questions also abounded about loyalties within his own power structure. In a January interview with a Spanish news outlet, he suggested threats had been made against his life.

“The president made too many enemies on all fronts,” said Louis Herns Marcelin, a sociocultural anthropologist at the University of Miami who studies Haiti. “He was a president who often didn’t listen to anybody except the little cliques and individuals that were way around him. … All of those things placed him at more risk.

“Keep in mind that people came into the compound with no resistance yet this was supposed to be the most protected man in the country,” Marcelin added.