U.S. officials said two U.S. Army military policemen were killed and 13 wounded when two mortars struck the Abu Ghraib prison in western Baghdad.

At about the same time, a U.S. Army soldier was killed when his vehicle hit a roadside bomb near Ramadi, about 100 kilometers west of the capital.

The Abu Ghraib prison has been the target of repeated guerrilla-style attacks this month.

At a news briefing, U.S. Army Spokesman Lieutenant Colonel George Krivo, offered no clues about what the attackers' motive might be. "I cannot speculate on what the enemy's strategy is on attacking this particular prison. I can tell you that coalition forces are taking both active and passive measures to try to prevent these sorts of attacks in the future. However, why the enemy is choosing a particular target or a particular methodology of attack, I cannot speculate on that," he said.

Meanwhile, the Iraqi Interior Ministry and coalition advisers are investigating Saturday's assassination attempt against Akila al-Hashimi, one of three women on the 25-member governing council.

Douglas Brand is a British police officer and Interior Ministry adviser. He told reporters about Ms. al-Hashimi's condition.

"Mrs. al-Hashimi has undergone two operations. She remains in critical, but stable, condition at the Abin Sinha hospital under the care of top U.S. doctors. There is an intensive investigation being undertaken by the Iraqi police service and supported by coalition advisers. Full cooperation has been extended to the Iraqi police service, in order that they may pursue the perpetrators of this crime," Mr. Brand explained.

Mr. Brand and the deputy interior minister, Ahmed Ibrahim, gave reporters no indication they have solid leads on who the perpetrators are.