"Criminals fired rockets and they hit the Jamila market. I don't know how many people they killed," Stover said. Police said a fire at the market destroyed 100 shops, blazing unchecked for hours because firefighters could not reach it.
BLOCKADE
U.S. and Iraqi forces have imposed a blockade on vehicle traffic in and out of Sadr City for two weeks. Residents of the besieged district describe skyrocketing food prices, rubbish piling up and claustrophobia from being trapped indoors.
"We haven't been able to sleep since this fighting started two weeks ago," said Wardan Ali, a student from Sadr City who walked 10 km (6 miles) to university because of the blockade.
Sadr's bloc in parliament denounced the raids.
"The intervention of U.S forces is horrible and unjustified. Some people in Sadr City believe these forces will hunt and kill them," said Hassan Hashem, a Sadrist member of parliament's security committee.
The fighting in Sadr City followed a joint call by Iraq's main factions, apart from the Sadrists, for all militias to hand over weapons, an apparent attempt to isolate Sadr.
Sadr has called for 1 million Iraqis to march against U.S. "occupiers" on Wednesday, when Crocker and Petraeus are due to conclude two days of testimony before the U.S. Congress.
The two top U.S. officials in Iraqi are expected to call for a pause in American troop withdrawals after 20,000 U.S. soldiers return home over the next four months.
Near the northern city of Mosul, at least 40 students on a bus were kidnapped by gunmen for several hours before Iraqi security forces freed them, said Brigadier-General Khalid Abdul-Sattar, security spokesman for Nineveh province.
The incident was a reminder of continuing unrest in Iraq's northern mixed and Sunni Arab areas at a time when attention is focused on violence in Shi'ite areas in Baghdad and the south.
"These are terrorist groups linked to al Qaeda and Saddam's former regime who are terrorising innocent people constantly," government spokesman Ali al-Dabbagh told Al Arabiya television.
Sunni Islamist al Qaeda has regrouped in northern provinces after being pushed out of western Anbar province and Baghdad.
