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BAGHDAD, June 11 (Reuters) - A suicide car bomber struck a major bridge in Iraq's volatile Diyala province on Monday, police said, cutting the span over the Diyala River.

Police said they did not know if there were any casualties. The bridge, normally guarded by Georgian troops, links the provincial capital Baquba with villages in the north of Diyala.

No other details were immediately available.

Three U.S. soldiers were killed and another six wounded when a suicide car bomber attacked a checkpoint near a bridge spanning a major north-south artery south of Baghdad on Sunday.

The explosion near Mahmudiya, in the notorious "triangle of death" area, brought down part of the bridge.

Insurgents have been targeting major bridges in Baghdad and surrounding areas as part of a new tactic. In April, part of the popular Sarafiya bridge over the Tigris River in Baghdad was destroyed.

Diyala, north of Baghdad, has seen some of the worst violence in Iraq since the U.S.-led invasion to topple Saddam Hussein in March 2003.

Attacks by insurgents, many of them blamed on Sunni Islamist al Qaeda and associated groups, have also increased since the start of a U.S.-led security crackdown in Baghdad began driving insurgents out of the capital into surrounding cities and towns.

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