PORT-AU-PRINCE, Haiti — Gangs on Thursday opened fire and hit a U.N. helicopter, forcing it to land in Port-au-Prince in the latest attack in Haiti’s capital as violence surges once again.

No one was injured as several rounds of gunfire hit the helicopter that was carrying three crew members and 15 passengers, according to a U.N. source who was not authorized to confirm the incident. The helicopter, which had departed from Port-au-Prince before it was attacked, landed safely, the source said.

The attack comes five months after Haiti’s main international airport reopened following coordinated gang attacks that forced it to close for nearly three months.

The violence has spilled to nearby areas including Arcahaie, where some 50 suspected gang members died this week after attacking the coastal town located just northwest of the capital. Among the dead are at least a dozen gunmen who drowned after their boat capsized, a government official said Thursday.

While the majority were killed by police, a group of gunmen drowned on Wednesday after their boat hit the reef as they ferried ammunition to gangs attacking the town of Arcahaie, said Wilner Réné from Haiti’s Civil Protection Agency.

He told Radio Caraïbes that the attack began on Monday, with gunmen burning homes and cars across Arcahaie.

When the gangs ran out of ammunition, they hid in nearby areas and were ferreted out by residents and police, he said.

The attack is still ongoing, and Réné warned that officers on the scene urgently need reinforcements from soldiers and special police units.

The attack is blamed on a gang coalition called Viv Ansanm, which also has targeted communities in Port-au-Prince in recent days. Those attacks have displaced more than 10,000 people in the capital in just one week, according to a report released Thursday by the U.N.’s International Organization for Migration. More than half of those left homeless crowded into 14 makeshift shelters, including schools. The remainder are temporarily staying with relatives.

The spike in gang violence comes just months after a U.N.-backed mission led by Kenyan police began with the aim of quelling a surge in violence from gangs, who control more than 80% of Port-au-Prince. More than 700,000 people have been left homeless, and thousands have been killed.

The U.S. government and top Haitian officials have warned that the Kenyan-led mission lacks personnel and funding and have asked that it be replaced with a U.N.-peacekeeping mission.

Coto reported from San Juan, Puerto Rico