The army hit militant forces in Hawiqa district on Tuesday with tanks and multiple rocket launchers, and also battled them in territory separating Hawiqa from the district of Joura, opposition sources in the city said.
The opposition Syrian Observatory for Human Rights monitoring group said two militants were killed in the battles on Tuesday. There were no immediate reports about casualties among Syrian forces.
The provincial capital on the banks of the Euphrates, 430 km (270 miles) northeast of Damascus, anchors a vast, arid oil-producing region bordering Iraq.
Half of it was occupied by anti-Syria militants a year ago but army soldiers have been able to keep secure several districts in the west of the city and areas between the local airport to the east.
Syrian army has been struggling with al-Nusra terrorists in south and east of the country, moving steadily forward to free occupied towns and villages.
The war in Syria started in March 2011, when pro-reform protests turned into a massive insurgency following the intervention of Western and regional states.
The unrest, which took in terrorist groups from across Europe, the Middle East and North Africa, has transpired as one of the bloodiest conflicts in recent history.
SHI/BA