Demonstrators blocked streets and burned tires in Haiti’s capital Port-au-Prince on Thursday after 11 police officers were killed over the last week due to gang violence that continues to grip the Caribbean nation.

Protesters blocked roads around the capital and in several cities to the north, with local media reporting that police officers angry over lack of government support to fight gangs were leading the demonstrations.

A group of demonstrators arrived at the official residence of Prime Minister Ariel Henry and then left for the Port-au-Prince airport, according to a Reuters witness.

Henry returned from a trip to Argentina for a conference on Thursday afternoon, according to two sources present at the airport.

Haiti’s National Police and the Prime Minister’s Office did not immediately respond to requests for comment.

The Vitelhomme gang last week killed four police officers near the capital, while shootouts with the Savien gang in the town of Liancourt left another seven officers dead on Wednesday, according to Haiti’s National Police and local media reports.

The upheaval comes as the United Nations discusses sending a foreign strike force to confront Haitian criminal groups, a proposal that was originally made three months ago.

No country has offered to lead such a force.