UNITED NATIONS (AP) — U.N. peacekeeping forces responded immediately to only a minority of attacks on civilians and almost never used force to protect them when they did respond, the U.N.’s internal watchdog said.

The Office of Internal Oversight Services said only 20 percent of the 507 attacks reported by Secretary-General Ban Ki-moon between 2010 and 2013 led to an immediate response by eight U.N. peacekeeping missions with a mandate to protect civilians that it evaluated.