MANILA, Philippines — The U.N. says it is suspending food distribution for hundreds of thousands of people displaced by violence in the southern Philippines following a string of deadly bombings blamed on Muslim rebels.

Alghassim Wurie, acting director for the U.N. World Food Program in the Philippines, says the decision was made out of concern for the staff’s security.

A bomb blast in Cotabato city on Sunday killed six people and wounded dozens, followed by another attack in Iligan city on Tuesday that wounded three soldiers and about 10 civilians. The WFP has offices in both cities.

The U.N. has provided food for 578,000 people affected by fighting between government troops and Muslim rebels since last August. About 348,000 are still displaced.