Haiti has asked Washington and the UN to send troops to help it secure its ports, airport and other strategic sites after the assassination of President Jovenel Moise, a government minister said Friday.

The United States has already said it will send FBI and other agents to Port-au-Prince, two days after Moise was brutally killed by gunmen in his home, opening up a power vacuum in the impoverished and crisis-hit Caribbean nation.

In the wake of the slaying "we thought that the mercenaries could destroy some infrastructure to create chaos in the country. During a conversation with the US Secretary of State and the UN we made this request," elections minister Mathias Pierre told AFP.

The US State Department and Pentagon both confirmed receiving a request for "security and investigative assistance" and said officials remain in contact with Port-au-Prince, but did not specify whether military troops would be deployed.

The UN did not immediately respond to a request for comment.

Washington had signaled its willingness to help the Haitian investigation, and White House spokeswoman Jen Psaki added Friday that senior FBI and other officials would be heading to the Caribbean as soon as possible.

Pierre confirmed that the request had been made as questions swirled Friday about who could have masterminded the audacious assassination, with most members of a hit squad of Colombians and Americans either dead or in custody, and no clear motive made public.

Amid the uncertainty, two men are now vying to lead the country of 11 million people, more than half of whom are under age 20. There is no working parliament.

After days of paralysis in the capital, Port-au-Prince saw the timid return of people to the streets, shops opening and the resumption of public transport on Friday morning -- but under a pall of apprehension.

People scrambled to stock up on basic necessities at supermarkets and lined up at gas stations to buy propane used for cooking in anticipation of more instability.

"I don't know what's going to happen tomorrow or the day after in the country, so I am preparing for bad days ahead," Port-au-Prince resident Marjory told AFP, as she and her husband stocked up on supplies at a store.

"I'm prioritizing everything that can last for many days."

Gang violence, rife in the Caribbean nation, also picked up again on Friday, with clashes between groups paralyzing traffic on a major highway.

The city's airport, shuttered in the wake of the attack, appeared to have reopened, according to Flightradar data.

Contract killers?

But as the shock of the killing wore off, many were demanding answers.

"Foreigners came to the country to perpetrate this crime. We, Haitians, are appalled," a resident of the capital told AFP.

"We need to know who is behind this, their names, their backgrounds so that justice can be served," he added.

Police have said a 28-member hit squad of Colombians and Americans had carried out the attack, but that they were still seeking its masterminds.

Senior police officers, directly responsible for Moise's security, are in the hot seat and have been summoned to appear before the courts.

Others have speculated on the possible involvement of security agents in the killing, adding to the confusion.

"The president of the Republic, Jovenel Moise, was assassinated by his security agents," former Haitian senator Steven Benoit said on Magik9 radio Friday.

"It is not Colombians who killed him. They were contracted by the Haitian state."

Political chaos

Some alleged attackers, including both Americans, have been arrested. Three have been killed, and at least five are still on the run, officers said Friday.

Some of the suspects were arrested after breaking into the Taiwanese embassy, Taipei confirmed. Several were paraded before the media on Thursday.

The US has said it is aware of the arrest of US citizens but declined further comment.

Colombia on Friday said 17 Colombian ex-soldiers were thought to have been involved. President Ivan Duque has told Haitian officials Bogota will collaborate in the investigation.

The attack has further destabilized the poorest country in the Americas, plagued by insecurity.

Haiti was already in the midst of in an institutional crisis: Moise had not organized an election since he came to power in early 2017 and the country has had no parliament since January 2020. Moise had been ruling by decree.

One of Moise's last acts as president on Monday was to appoint a new prime minister, Ariel Henry. He had not taken office when Moise was killed.

Hours after the assassination, Henry's predecessor Claude Joseph said he was in charge.

While the opposition has accused Joseph of power-grabbing, the United Nations envoy to Haiti, Helen La Lime, has said he had authority because Henry had not been sworn in.