BEIRUT, Dec 12: An explosion targeted the Syrian Interior Ministry building Wednesday in the capital, Damascus, state TV said. There was no immediate word on casualties.

Rebels fighting to overthrow Syrian President Bashar Assad have been making inroads in their advance toward Damascus, the seat of the government, in recent weeks.

Fighting has intensified in the southern districts of the Syrian capital and its suburbs.     Rebels have targeted the centre of Damascus with bomb attacks in the past, most dramatically in July when they detonated explosives inside a high-level crisis meeting in Damascus that killed four top regime officials, including Assad's brother-in-law and the defence minister.

An Al Qaeda linked group, Jabhat al-Nusra, has claimed many deadly blasts inside Syria.    On the political front, more than 100 countries recognised a new opposition coalition as the legitimate representative of the Syrian people during an international meeting being held in Morocco. The US also has declared the coalition is the “legitimate representative” of its country's people. The moves open the way for greater humanitarian assistance to the forces battling Assad and possibly even military aid.

But the presence of extremist groups among the rebel forces has raised concerns in the US and other nations that are supporting the opposition in Syria but do not want to see extremists gain power in the region. The US has blacklisted Jabhat al-Nusra — Arabic for Victory Front — as a foreign terrorist organisation and said the group was part of Al Qaeda in Iraq.

Al-Nusra fighters appear to be among the most effective fighting forces on the rebel side, spearheading many recent gains. Western officials have raised concerns that an increasingly desperate Assad might unleash his chemical weapons stockpiles against rebels.

Syria is believed to have a formidable arsenal of chemical weapons, including sarin and mustard gas, although its exact dimensions are not known. Syria is not a signatory to the 1997 Convention on Chemical Weapons and thus is not obliged to permit international inspection.

The government in Damascus has been careful not to confirm it has chemical weapons, while insisting it would never use such weapons against its own people.—AP