The 82 mm mortar round crashed into the Civil Military Operations center, an office that coordinates military and civilian humanitarian aid, on Wednesday.

US soldiers said they contacted local police after hearing three explosions. Police arrived at the scene and found the dead and wounded, the statement said.

"Soldiers were unable to respond or find the perpetrators," said the statement, from US Central Command.

"This is one of numerous incidents recently where Iraqi resistors have attacked coalition forces or Coalition Provisional Authority locations and injured or killed Iraqi citizens," it said.

The statement said that no US forces were injured in the attack and that the incident was under investigation.

It was the third known mortar attack on coalition facilities since major combat was officially declared over on May 1.

Iraqis have been stepping up their attacks on US forces in recent weeks. Authorities have blamed members of Saddam Hussein's ousted Baath Party, ex-army soldiers, non-Iraqi "holy warriors" and Sunni Muslim radicals for the surge in violence.

In a shift of tactics, insurgents this week began targeting fellow Iraqis deemed to be too close to the US-led occupation.

(China Daily June 20, 2003)