The “alleged assassins” of Haiti’s President Jovenel Moise were in custody Wednesday, a government minister said, less than 24 hours after the leader of the impoverished Caribbean nation was killed in a gun attack at his home.

“Alleged assassins of (Moise) intercepted by the National Police in Pelerin shortly before 6 pm tonight,” deputy communications minister Frantz Exantus tweeted, adding that more details would be released shortly.

Haiti President Jovenel Moise was assassinated and his wife wounded early Wednesday in a gun attack at their private residence, tipping the impoverished and crisis-hit Caribbean nation into renewed political uncertainty.

Interim Prime Minister Claude Joseph declared a national “state of siege” and said he was now in charge of the country, urging people to remain calm while insisting the police and army would ensure public order.

As international outrage and shock spread over the killing, the airport was closed in the capital Port-au-Prince, but witnesses said the city was quiet with the streets deserted and no extra security forces on patrol.

“The president was assassinated at his home by foreigners who spoke English and Spanish,” Joseph said of the assault that took place around 1:00 am (0500 GMT).

“This death will not go unpunished,” Joseph said in an address to the nation.

Moise’s wife Martine was first treated in a local hospital before being evacuated to Miami. A Miami Herald correspondent tweeted that she had landed in nearby Fort Lauderdale by air ambulance Wednesday afternoon.

Haiti’s ambassador to Washington, Bocchit Edmond, told reporters the killers were “professional” mercenaries who disguised themselves as US Drug Enforcement Administration agents and may have already left the country.

“We have a video and we believe that those are mercenaries,” he added.

Moise had ruled Haiti, the poorest country in the Americas, by decree after legislative elections due in 2018 were delayed in the wake of disputes, including on when his own term ends.

In addition to the political chaos, kidnappings for ransom have surged in recent months, reflecting the growing influence of armed gangs in the country.

Haiti also faces chronic poverty and recurrent natural disasters.

The Dominican Republic ordered the immediate closure of its border with neighboring Haiti after the assassination.