Syrian troops pressed an advance Thursday on the strategic area of Sfeira, the site of several arms factories near Aleppo, said the Syrian Observatory for Human Rights.

"Fierce clashes are raging between the rebels and regime troops on the eastern side of Sfeira, amid a loyalist advance on the town, as troops take control of a new area," said the Britain-based Observatory.

Battles have raged in the Sfeira area near second-city Aleppo for several months. The area is important because of the arms factories and because it is located on a key route linking Aleppo to central Syria.

Sfeira has been under rebel control for a year, but the factories have remained in army hands.

The army advance opens up the loyalists' entry to Aleppo city, which has seen intense fighting since a massive rebel advance on July 20, 2012. Some parts of the city are already controlled by the regime while others are in rebel hands.

Elsewhere, several mortar shells launched by rebels hit Jaramana, a majority Christian-Druze suburb of Damascus, said the Observatory.

The attack killed two women and wounded several other people, the group added.

The Britain-based Observatory, which relies on local activists and other witnesses, reported a series of explosions Wednesday at an air base in the western Latakia province, a regime stronghold.

"Several explosions were heard in an air defence base in the Snubar Jableh area" on Wednesday, said Observatory director Rami Abdel Rahman.

He said the cause of the explosions is "unclear" and that no casualties have been reported.

A Syrian security source meanwhile told AFP that "a rocket fell near the base, causing a fire to break out."

Latakia is a stronghold of President Bashar al-Assad's regime, and is home to a large number of Alawites, who belong to the same minority Shiite sect as the country's embattled ruler.