US troops in Sadr City in Baghdad

U.S. military officials says intense fighting in Iraq has made April the deadliest month for American soldiers in the country since September.

Officials say at least 47 U.S. soldiers have died in fighting during the month.

Meanwhile, Iraqi officials have revised the over-all death toll sharply upward from fighting that began last month in the Shi'ite stronghold of Sadr City, in Baghdad.

A spokesman for the Iraqi government's Baghdad security operations says 925 people have been killed in Sadr City. The spokesman, Tahseen al-Sheikhly, said Wednesday that 2,600 others have been wounded.

Sadr City has been the scene of fierce clashes pitting U.S. and Iraqi forces against Shi'ite militiamen loyal to radical cleric Moqtada al-Sadr.

The death toll announced Wednesday is much higher than previous estimates, which indicated about 400 people had been killed in Sadr City in the past month.

Meanwhile, Iraqi Prime Minister Nouri al-Maliki has vowed to disarm militias by force and disband the Shi'ite Mahdi Army, Sunni insurgent groups and al-Qaida in Iraq.

Mr. Maliki also ordered a crackdown last month on Sadr's Mahdi Army in the southern city of Basra.

In other news, the U.S. military says Iraqi police are conducting an investigation along a route often used by morning commuters in northern Kirkuk City, and outside shops in the city. Two bomb blasts there on Tuesday wounded 14 civilians and three Iraqi Army personnel. Reports say another civilian may have died.