The U.S. military says four American soldiers have died in separate attacks in Baghdad.

Three of the soldiers were killed Monday in east Baghdad, where U.S. and Iraqi troops have waged intense battles with Shi'ite militiamen. The fourth soldier was killed by indirect fire during a separate incident in western Baghdad.

Earlier, the U.S. military reported it had killed seven militants in Baghdad's Sadr City district. The casualties came during a combined air and ground assault launched in response to small arms fire directed at U.S. troops.

On Sunday, Iraqi and American troops killed 38 suspected militants in Baghdad, in the fiercest fighting in weeks. Officials said gunmen took advantage of a sandstorm that blanketed the Iraqi capital to launch apparently coordinated assaults.

The sandstorm grounded American helicopters, the main weapon used by U.S. forces to hunt insurgent rocket-launching crews.

Some information for this report provided by AP and AFP.