Haiti has asked for foreign troops to be sent to the country to protect key infrastructure after the assassination of President Jovenel Moïse.
The request was sent by the government to the US and the UN, but the US says it has no plans to offer military assistance “at this time”.
Haitian police earlier said a group of 28 foreign mercenaries killed the president on Wednesday.
After a gun battle in the capital Port-au-Prince, 17 of them were detained.
Some of the group, which Haiti says included retired Colombian soldiers, were held at the house they were using, others after entering Taiwan’s diplomatic compound, the police said.
Three suspects were killed by police, and eight others are still being sought.
Although the US will not offer troops, it said on Friday it was sending FBI and Department of Homeland Security officials to Haiti to help in the investigation.
The UN Security Council would have to approve any plan to send international troops to Haiti under UN auspices.
The killing has triggered some civil unrest in Haiti, the poorest nation in the Americas. A state of emergency remains in force across the country and it is unclear who is in effective charge of the country’s government.
Firearms and cash
Bloodied and bruised, arrested suspects were shown to the media on Thursday, along with a slew of seized weapons.
It is still unclear who organised the attack and with what motive.
The attack took place in the early hours on 7 July, when gunmen broke into the president’s home, shooting him dead and wounding his wife. Mr Moïse, 53, was found lying on his back with 12 bullet wounds and a gouged eye, according to the authorities.
Police said the hit squad included mainly Colombians, along with two Haitian-Americans.
Found in the suspects’ possession were firearms, sets of US dollar bills, the president’s personal chequebook and the server that held surveillance camera footage from his home, Le Nouvelliste newspaper reported.