U.S. tanks and snipers took up positions near the revered Imam Ali Shrine and engaged in fierce battles with militants as the U.S. military stepped up pressure on the insurgents to leave the holy site and end their uprising.
Late Monday night, U.S. warplanes bombed the area of the Old City, and fires lit up the night sky, witnesses said. Shrapnel from the attack hit the shrine's golden dome, one of its minarets and the compound's outer wall, said Ahmed al-Shaibany, an aide to Muqtada al-Sadr, the militant cleric whose followers are behind the uprising.
The military denied damaging the shrine and said an air crew saw militants holed up there fire a rocket that clipped one of the compound's walls and exploded 10 yards outside.
"We are not doing anything that could have caused damage to the shrine," Marine Capt. Carrie Batson said.
There was no independent confirmation of damage to the shrine, but violence earlier Monday ripped a chunk out of the outer wall of the compound.
In other recent developments:
With the U.S. advance Monday, fewer militant fighters were visible in the streets of Najaf and some were seen leaving the city. Militant medical officials said at least two insurgents were killed and four others injured.
Al-Hakim Hospital reported two dead civilians and two others injured, but many more casualties were reported in the Old City and could not be reached by emergency workers, said Hussein Hadi, a hospital employee.
Al-Sadr himself has not been seen in public for many days, and police drove around Najaf with loudspeakers declaring that he had fled and was headed to the northern city of Sulaymaniyah. Al-Sadr's aides denied that.
"Muqtada al-Sadr is still in Najaf and is still supervising the operations," Sheik Aws al-Khafaji, the head of al-Sadr's office in the southern city of Nasiriyah, told the pan-Arab television station Al-Jazeera.
Worries that the violence could spread have fueled calls by Iraq's neighbors and other Islamic countries for international intervention to end the fighting in Najaf.
In Baghdad's heavily Shiite Sadr City neighborhood, which has been wracked by violence since the Najaf uprising, an explosion Monday killed four people and injured nine others, said Dr. Qasim Saddam, director of Sadr Hospital. The cause of the blast was unclear, and the U.S. military said it was unaware of the incident.