Police in Haiti have killed at least three people while repelling an attack on the country's central bank.

A "group of criminals" targeted the Bank of the Republic of Haiti (BRH) on Monday, an employee told AFP, leaving up to four dead and a guard injured.

The bank itself thanked security forces for "protecting our community".

Haiti has been rocked by weeks of violence after gangs raided prisons, released thousands of inmates and forced the prime minister to resign.

Haiti's embattled Prime Minister Ariel Henry agreed to resign late Monday following days of mounting pressure, as the last vestiges of law and order in the Caribbean country have collapsed.

Henry, who is stranded in Puerto Rico, made the announcement in a video address. Heavily armed gangs have taken control of and attacked the country's government infrastructure, including Haiti's only international airport.

A regional bloc has summoned Caribbean, North American and European leaders and envoys to an emergency summit on the crisis in Haiti as attempts by gangs to wrest control from the crisis-racked country’s prime minister has caused further chaos.

The Caribbean Community (CARICOM) called the meeting on Monday in Jamaica’s capital, Kingston, as more foreign diplomats were evacuated from Haiti, including European Union staff and all non-essential US personnel.

Haiti advocates in the United States are calling on the Biden administration to rethink its approach toward the country amid gang warfare threatening to topple the U.S.-backed government.

Haitian acting Prime Minister Ariel Henry is in Puerto Rico, unable to return to his country under threat of “civil war” by an alliance of gangs.

Henry had left Haiti on a mission to secure a Kenya-led police force to supplement the Caribbean nation’s own police in a U.S.-backed attempt to prop up his government.

The U.S. military has sent forces to Haiti to airlift nonessential staff from the U.S. embassy and help bolster security amid gang violence plaguing the Caribbean nation. 

U.S. Southern Command told Fox News Digital that U.S. Military forces conducted an operation at the request of the State Department to bolster the security of the U.S. Embassy at Port-au-Prince. 

The U.S. military carried out an evacuation mission of U.S. Embassy staff in Port-au-Prince, Haiti, amid a deteriorating security situation.

The State Department requested the military carry out the mission to both airlift non-essential personnel out of the capital and to increase the security posture at the embassy, according to a statement from U.S. Southern Command.

There were no Haitians on the military aircraft, the military said, signaling that no senior Haitian government officials were fleeing.

The United States called for its citizens to leave Haiti "as soon as possible" after violence escalated late last week, when 15,000 more people fled the fighting and armed men broke thousands of inmates from Haiti's largest prison.

The United States, which is home to over a million Haitians, said its embassy would be offering limited operations on Monday while Canada said it would temporarily close its embassy.

Armed gangs in Haiti's capital released roughly 4,000 inmates from the country's largest prison after a days-long gun battle with police on Sunday.

The vast majority of the 4,000 men held in the Port-au-Prince jail successfully escaped, according to reports from local media. Many of the inmates were gang members charged in connection with the 2021 assassination of Hatian President Jovenel Moise.

Authorities in Haiti have ordered a nighttime curfew after an explosion of violence when gang gunmen overran the two biggest prisons and freed thousands of inmates over the weekend.

A 72-hour state of emergency began Sunday night. The government said it would set out to find the killers, kidnappers and other criminals who fled.

“The police were ordered to use all legal means at their disposal to enforce the curfew and apprehend all offenders,” said a statement from Finance Minister Patrick Boivert, the acting prime minister.

U.S. rice exports to Haiti, which account for the bulk of supplies of the country's key food staple, contain unhealthy levels of arsenic and cadmium, heavy metals that can increase risks of cancer and heart disease, according to a recent study by the University of Michigan.

Haiti is among the United States' top buyers of rice, alongside Mexico and Japan, and cheap imports are more affordable than local options in the Caribbean nation, the poorest state in the Western Hemisphere.