DAMASCUS, Syria (AP) -- Syrian troops advanced in a strategic suburb of Damascus and bombarded other areas around the capital Saturday in a push to secure President Bashar Assad's seat of power as rebels make gains in the north.

A government official said regime forces had taken much of Daraya, an area on the edge of a major military air base just south of the capital, after nearly two months of heavy fighting that anti-regime activists say has killed dozens of people and uprooted tens of thousands more from their homes.

The announcement came a day after rebels and Islamic militants seeking to topple Assad took full control of the northwestern Taftanaz air base in a significant blow to the military. The back-to-back declarations highlight the see-saw nature of the conflict in Syria, where one side's victories in one area are often followed by reverses in another.

In other violence, athletic champion Hisham Raqsha was shot to death in Damascus while on his way back home, according to the Observatory and state-run news agency SANA. SANA said Raqsha was the coach of Syria's walking team. His age and other details were not available.

Syrian troops have been battling since November to regain Daraya from the hands of anti-government fighters. The suburb is flanked by the key districts of Mazzeh, which is home to the military air base of the same name, and Kfar Sousseh, which holds the government headquarters, the General Security intelligence agency head office and the Interior Ministry.

It also is less than 10 kilometers (six miles) from the People's Palace -- one of three palaces in the capital used by Assad.

The government official told The Associated Press in Damascus that the army still faced "small pockets" of resistance but he expected the area to be cleared in a few days. The official spoke on condition of anonymity in line with regulations.

Rami Abdul-Rahman, who heads the Britain-based Syrian Observatory for Human Rights, acknowledged "the army has entered most of Daraya's neighborhoods." He added the number of casualties on both sides was high after weeks of fighting.

"Daraya is very important for the regime because the Mazzeh airport is a main artery for it," Abdul-Rahman said.

Daraya, which had a population of about 200,000 before the fighting, has been a stronghold of support for the rebels fighting the government since the start of the uprising in March 2011, posing a particularly grave threat to the capital.

In August, troops backed by tanks stormed the town after several days of siege, with hundreds reportedly killed. Most residents have fled to safer areas since the latest offensive began, leaving only about 10,000 civilians who are facing electricity cuts and dwindling food, fuel and medical supplies. A heavy snow storm last week only worsened the suffering of those left behind.

The Local Council opposition group says more than 1,300 people have been killed in Daraya since the uprising began. The council says 1,000 of its residents are in Assad's jails. Claims by both sides are impossible to verify because of restrictions on reporting in the country.

Today, those entering Daraya have to pass through government checkpoints at its gates or sneak through the fields escorted by rebels. Young men with automatic rifles and black headbands with Islamic writings manned checkpoints inside the suburb, which is controlled by members of the Furqan Bridage and other battalions known as Dayara Martyrs, Ababil and Houran.

A visit to the area earlier this week showed the desperate circumstances facing the residents under siege.

Earlier this week, one man who stood in front of his destroyed apartment said he had taken his family to Damascus for safety and returned to get some belongings. "As you can see, my home is totally destroyed. May God help me," the man said.

Inside a makeshift hospital, a medical student who identified himself only as Samih was trying to remove shrapnel from the shoulder of a rebel on a stretcher. "I haven't slept for two days," Samih said, also complaining about lack medical supplies.

Syria's pro-government media had reported that thousands of rebel fighters from the extremist Jabhat al-Nusra group have holed up in Daraya in preparation to storm Damascus.

Jabhat al-Nusra, which has been branded a terrorist organization by the U.S. and which Washington claims is affiliated with al-Qaida, has been among the most effective fighting forces on the rebel side. Syrian official statements regularly play up the role of Islamist extremists in the civil war and refer to the rebels as terrorists.

Syrian TV reported Saturday afternoon that Syrian troops are "chasing the remnants of armed terrorists groups in Daraya, killing a number of snipers."

The Observatory said other Damascus suburbs also were being shelled on Saturday and a car bomb exploded in the suburb of Sbaineh, causing heavy damage. It was not clear if the blast caused casualties, it said.

An amateur video posted online by activists showed several heavy damaged buildings by the blast. The video appeared genuine and corresponded to other AP reporting on the events depicted.

The group also said Syrian warplanes attacked eastern suburbs of Damascus including Mleiha, as well as the rebel-held town of Rastan near the central city of Homs.

More than 60,000 people have been killed since the 22-month conflict started.

Rebels maintained control of the Taftanaz field in Idlib province on Saturday and intensified their assault on the Mannagh air base and the international airport of the city of Aleppo, which includes a military base, activists said.

Syrian TV reported Saturday that the army repelled attackers targeting Aleppo's Kishek airport and inflicted casualties. It gave no further details. The Observatory reported Saturday that warplanes carried out air raids around the Aleppo airport.

On the diplomatic front, Russia, one of Assad's last remaining allies, said Saturday it is still strongly against any foreign interference in Syria's affairs.

"As before, we strongly believe that all the issues concerning Syria's future must be decided by the Syrians themselves, without outside interference or the imposition of ready-made recipes for development," the Russian Foreign Ministry said in a statement.

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Mroue reported from Beirut. Associated Press writers Nataliya Vasilyeva in Moscow and a journalist in Daraya, Syria, contributed to this report.