Updated

Syrian government troops pushed Thursday into the central districts of the city of Homs in an effort to oust rebels from the country's third largest urban center, activists said.

Homs, along with the capital of Damascus and Syria's largest city, Aleppo, has been a key battleground in the country's conflict, which is now in its third year and which has claimed more than 70,000 lives.

The Britain-based Syrian Observatory for Human Rights said troops loyal to President Bashar Assad regained control of the Wadi Sayeh district in the center of Homs by early Thursday morning.

The neighborhood is strategically important for the government as its forces try to dislodge opposition fighters from several of Homs' central districts that have been under rebel control for more than a year. There were no immediate reports of casualties from the latest fighting.

The Syrian conflict started with protests against Assad's regime in the impoverished suburbs of the major cities, but quickly spread around the country, descending into a full-scale civil war.

In recent weeks, government forces have been on a counter offensive to reverse rebel gains in and around Aleppo, where the opposition controls whole neighborhoods and large swaths of land around the city.

The army has also conducted massive sweeps through opposition strongholds around Damascus to oust rebels from their enclaves, from where they are increasingly threatening the capital, the seat of Assad power.

Regaining full control of Homs would be a psychological blow to the opposition, which holds the city as a symbol of Syria's uprising, inspired by other Arab Spring revolts against authoritarian rulers around the Middle East.

Homs was the scene of massive street protests against Assad's regime in the first months of the uprising that began in March 2011. Since then, it has seen some of the worst urban warfare in the country's civil war.

Activists with the Observatory's network of informants said Assad's warplanes on Thursday hit several targets in Damascus province, including rebel positions in neighborhoods around the capital, as well as targets in the southern city of Daraa.

Opposition activists also reported fierce clashes between Assad's troops and rebels in Aleppo, Syria's main commercial hub. The city has been carved up into opposition- and government-held areas since the rebels launched an offensive there last summer, capturing several Aleppo districts and villages and towns around the city, which is near the border with Turkey.

Syria's state-run SANA news agency said three people were wounded in a mortar attack on the northern Damascus district of Abbasid on Thursday. The district is located near the neighborhood of Jobar, from where rebels have been trying to push into the capital in the past weeks.

In another part of Damascus, a bomb attached to a car detonated, wounding one man and causing material damage, SANA said.

Earlier this week, two massive blasts went off in central Damascus, which has so far been spared the scale of destruction that Aleppo and other cities have sustained in the war.

On Tuesday, a powerful bomb rocked a busy commercial district, killing 13 people, the Syrian state TV said. A day earlier, Syria's prime minister narrowly escaped an assassination attempt after a car bomb struck near his convoy in a nearby area in Damascus.

The bombings appear to be part of an accelerated campaign by opposition forces seeking to strike at Assad's heavily protected seat of power.