Fighters also seized control of the highway linking the predominantly Sunni Muslim town with the besieged city of Falluja, west of Baghdad.
Hundreds of fighters armed with rocket-propelled grenades and Kalashnikov assault rifles were running along the highway, an AFP correspondent said.
An AFP photographer reported earlier that fierce clashes pitted US occupation troops against fighters in Abu Gharib.
In Baquba, a mixed Shia and Sunni town, fighting erupted on Friday with fighters clashing with US troops and targeting buildings, witnesses said.
They said smoke was rising from the governorate building housing US forces and from buildings surrounding the police station.
The sound of explosions was also heard near the main US base in the town, 65 km north of Baghdad.
The fighting erupted after supporters of radical Shia cleric Muqtada al-Sadr and sympathisers of Sunni fighters took to the streets to demonstrate after Friday's prayers.
West of Heet city on Friday, an explosion hit a US patrol, causing casualties and damaging a number of military vehicles, our correspondent reported.
An explosion also rocked Kirkuk airport, where US forces are based, said our correspondent.
And in Diyala province, clashes have erupted around the governor's office, causing casualties and damaging a US tank.
Meanwhile, Samir Sumaidy, a Sunni Muslim political independent on the US-installed Iraqi Governing Council, has been appointed interior minister. Mowaffaq al-Rubaie, a Shia independent, has taken over as national security adviser.
Sumaidy came in place of Nuri Badran who resigned as interior minister on the directive of occupation administrator Paul Bremer on Thursday. Badran quoted Bremer as saying that both the interior and defence ministry should not be headed by the Shia.