Nearly 20 of the roughly 400 Kenyan police officers serving in Haiti on a U.N.-backed anti-gang force have submitted letters of resignation from the mission over the past two months because of pay delays and poor conditions.

The officers have received no response to their letters and continue to serve on the Multinational Security Support (MSS) mission.

National police chief Douglas Kanja addressed reports in Kenyan media of pay delays at a news conference on Wednesday, saying the officers had been paid “up to the end of October”.