BEIRUT (Reuters) - Syrian rebels backed by radical Islamists captured a northern regimental command centre of President Bashar al-Assad's army, activists said on Sunday, as Russia dismissed speculation that it is preparing for its ally's possible exit from power.
Assad's forces hammered rebel units on the outskirts of Damascus as they tried to drive back opposition fighters rebels seeking to advance toward the embattled leader's seat of power.
Rebels have made a series of advances in recent weeks, partly due to help from radicals such as Jabhat al-Nusra, a group linked to Al Qaeda in Iraq which has been excluded from a newly-formed rebel military command.
The Syrian Observatory for Human Rights said Jabhat al-Nusra, w hich has called for the creation of an Islamic state in Syria, had participated in capturing the command centre of the army's 111th regiment in the north of the country. It said around five soldiers were captured, while the commanding officer and some 140 of his men fled to another army site nearby.
Russia, Syria's main arms supplier, dismissed suggestions from observers that its support for Assad might be softening.
"We are not holding any talks on the fate of Assad," Russian Foreign Minister Sergei Lavrov said after meeting U.S. Secretary of State Hillary Clinton and special U.N. envoy to Syria Lakhdar Brahimi. "All attempts to present the situation differently are rather shady," Itar-Tass news agency quoted him as saying.
Washington and its NATO allies, who have thrown their weight behind the opposition, are pressing for Assad's departure to end the conflict in Syria, which has taken more than 40,000 lives.
Russia and China have blocked U.N. resolutions against Assad, saying they oppose foreign intervention in the conflict.
However, Western officials have recently cited intelligence reports that Assad may turn to chemical weapons. "We have seen enough evidence to know that they need a warning and they have received a warning and I hope they heed that," British Foreign Secretary William Hague said on Saturday.
Syria has repeatedly denied the charges and accused the West of creating pretexts for foreign intervention.
Rebels have seized several military bases in recent weeks, although some activists on the ground say there is no sign they are on the verge of toppling Assad.
The rebels' capture of the regimental command centre in the Sheikh Suleiman region of Aleppo province, however, shows growing cooperation and even allegiance to radical Islamists who have proven to be some of the most effective fighters.
It is unclear how much Jabhat al-Nusra's exclusion from the newly-formed rebel military command in Syria, an effort backed by Western, Turkish and Arab security officials, will affect efforts to unify rebel ranks and increase financial support.
Led by Brigadier Selim Idris, the new command structure itself is also Islamist-dominated, though it has the backing of many Western states which have expressed reluctance to support the rebels due to the presence of radicals.
Radical groups such as Jabhat al-Nusra are small compared with other factions but their influence has grown in recent months, partly due to their successful operations. Some residents and rebels also believe the hardliners are more disciplined than some rebels who have been accused of looting and kidnapping.
Damascus has become a focal point of battles over the past week, as rebels effectively shut the international airport by clashing with Assad's forces there. Foreign flights have been suspended and residents say the airport road is closed.
Rebels who have dubbed their campaign "Operation Opening the Road to Damascus", uploaded video on Sunday that showed heavy gunbattles and explosions rocking several rural towns around the capital. The video also showed rebels firing a fully functioning tank which they had captured from the army.
But there is no clear winner yet in a battle where neither side seems to have advanced. The Syrian army has claimed many successes around the capital, airing footage on state television of soldiers raiding parts of the rebel stronghold of Deraya.
"Our noble forces in Deraya have destroyed some of the terrorist dens used by al Qaeda terrorists to store weapons and other criminal tools," said a report on Syria TV, which usually refers to rebels as terrorists. "Many terrorists were killed."
Syrian soldiers also freed an Iranian diplomat captured on the outskirts of Damascus on Saturday, according to Iran's state-run Arabic news channel Al-Alam. Majeed Adeli, the cultural attaché at the Iranian embassy in Damascus, had been kidnapped by rebels in the Sayyida Zeinab suburb.
Rebels have been targeting Iranians in Syria, many of whom it accuses of belonging to Iranian security forces. Iran has been Assad's main bankroller and backer in the region. Rebels are also holding 48 Iranians which Tehran says were pilgrims. (editing by David Stamp)