More than 30 US citizens landed in Florida on a chartered government flight from Haiti Sunday, the US State Department said, after weeks of gang violence that have paralyzed the Caribbean nation.

The flight departed from Haiti's port city of Cap-Haitien, where the airport has been open "periodically," according to the US embassy.

"The Department of State facilitated the safe departure from Cap-Haitien, Haiti of over 30 US citizens on a US government charter flight," a State Department spokesperson told AFP late Sunday.

"These passengers are now safely in Miami, Florida, where US government officials are assisting with next steps," they said.

Haiti has been convulsed for the last two weeks by a gang uprising aiming to topple unpopular Prime Minister Ariel Henry.

The well-armed groups have seen their numbers grow after an attack on two prisons freed thousands of inmates.

A recent United Nations report warned of the "near-collapse of basic services" in Haiti.

The chaos has left millions vulnerable as they await the formation of a transitional governing council to take power after Henry announced his resignation Monday under pressure.

For Americans remaining in Haiti, the State Department is "examining options for departures out of (the capital of) Port-au-Prince and will inform US citizens about them as soon as we are able to safely and securely arrange them," the spokesperson said Sunday.

"We will continue to assist US citizens as long as commercial options remain unavailable and the security environment permits us to do so," they added, urging US citizens seeking to leave Haiti to get in touch via their website.

The United States said last Sunday it had airlifted non-essential American staff from its embassy in the capital Port-au-Prince and brought in additional personnel to boost security at the compound.

Several other countries and the European Union have evacuated diplomatic personnel due to the crisis.

The United Nations also said it was evacuating non-essential staff.

Kenya has offered to lead an international security mission to back-up Haiti's overwhelmed police, as a state of emergency in the Western Hemisphere's poorest nation is set to end 3 April.