Iraq has seen a surge in violence in recent days. In the past week, a bombing in Baghdad killed three U.S. soldiers and wounded nine others.

Another bomb went off inside a police station killing three Iraqi officers.

And a suicide bomber killed a group of Sunnis waiting in line to get their paychecks.     

The bombings are adding pressure on an Iraqi government trying to prove it can handle security challenges ahead of a U.S. withdrawal from Baghdad and other cities at the end of next month.