Armed gangs have stormed the main prison in Haiti's capital Port-au-Prince, releasing many inmates.

The vast majority of about 4,000 men held there have now escaped, a local journalist told BBC News.

Among those detained were gang members charged in connection with the 2021 killing of President Jovenel Moïse.

Violence in Haiti, the poorest country in the Americas, has worsened in recent years. Gangs aiming to oust PM Ariel Henry control 80% of Port-au-Prince.

The latest upsurge in violence began on Thursday, when the prime minister travelled to Nairobi to discuss sending a Kenyan-led multinational security force to Haiti.

Gang leader Jimmy Chérizier (nicknamed "Barbecue") declared a co-ordinated attack to remove him.

"All of us, the armed groups in the provincial towns and the armed groups in the capital, are united," said the former police officer, who is thought to be behind several massacres in Port-au-Prince.

A wave of shootings left four police officers dead and five injured. The French embassy in Haiti advised against travel in and around the capital.

Haiti's police union asked the military to help reinforce the prison, but the compound was stormed late on Saturday.

On Sunday the doors of the prison were still open and there were no signs of officers, Reuters news agency reported. Three inmates who tried to flee lay dead in the courtyard, the report said.

One volunteer prison worker told the Reuters journalists that 99 prisoners - including former Colombian soldiers jailed over President Moïse's murder - had chosen to remain in their cells for fear of being killed in crossfire.

Violence has been rife since President Moïse's assassination. He has not been replaced and elections have not been held since 2016.

Under a political deal, elections were to be held and the unelected Mr Henry was due to stand down by 7 February, but that did not happen.

In January, the UN said more than 8,400 people were victims of Haiti's gang violence last year, including killings, injuries and kidnappings - more than double the numbers seen in 2022.