Baghdad ? The bombing of a Baghdad bus station Thursday pushed the death toll from a weeklong series of blasts near Shiite targets to about 200, calling into question Iraq’s ability to provide security as U.S. combat troops slowly withdraw from cities.

The wave of attacks is undermining Prime Minister Nouri al-Maliki’s declaration of a “great victory” in the U.S. pullout from urban areas by next Tuesday’s deadline. He has declared June 30 a national holiday to be marked with celebrations.

Al-Maliki, a Shiite, has pinned his re-election hopes largely on security gains that have driven violence to wartime lows — an issue that’s become his stump speech in an undeclared campaign for a second term. Seven months before national elections, he tells audiences that he’s quashed major violence, dismembered al-Qaida and stamped out Shiite militias.