A series of rebel attacks in Iraq have killed some 25 people as U.S. officials pledge to investigate recent "friendly fire" killings.

A suicide attack killed at least 15 people and wounded nearly two dozen more north of Baghdad. Nearby in Baquba, rebel attacks on Iraqi soldiers and police killed at least 10 people.

Also Monday, Iraqi officials issued new photos of wanted Jordanian terrorist Abu Musab al Zarqawi, showing him with short hair and a closely cropped beard. His group reportedly claimed responsibility for several of Monday's attacks.

Also today, Bulgaria's defense minister Nikolai Svinarov says an investigation shows U.S. troops were probably responsible for the shooting death of a Bulgarian soldier last Friday. That same day, U.S. troops shot dead an Italian intelligence agent at a checkpoint. U.S. officials have ordered investigations into both incidents.

Some information for this report provided by AFP and AP.