Syrian government forces have taken several key villages north of the city of Aleppo as they press an advance that could break a long-running rebel siege of two Shiite villages.

On Tuesday, Syrian state news agency SANA said government troops backed by pro-regime militants had "restored security and stability to the village of Hardatneen."

The capture was also reported by the Syrian Observatory for Human Rights, a Britain-based monitor, which said government forces had also seized part of the nearby village of Ratyan.

The advances come after regime forces, backed by Russian air strikes, seized two other villages in the area on Monday.

They bring government troops within five kilometres (three miles) of the Shiite villages of Nubol and Zahraa, which are under regime control but have been besieged by rebel forces for over two years.

Observatory chief Rami Abdel Rahman said the capture of Ratyan and one smaller village could allow regime forces to effectively break the siege on Nubol and Zahraa, a longstanding government goal.

Abdel Rahman said the government advance was being aided by dozens of air strikes by Russian forces, who entered the conflict in late September seeking to bolster President Bashar al-Assad's government.

He said more than 15 regime fighters and over 20 rebels had been killed in the fighting since Monday, but had no specific toll.

The government advance comes almost exactly a year after a similar regime offensive aimed at reaching Nubol and Zahraa and severing rebel supply lines into Aleppo city.

The city has been divided between government control in the west and rebel control in the east after fighting there began in mid-2012.

The situation is largely reversed in the surrounding countryside, with rebels controlling much of the area west of the city, and the regime present to the east.

Last year's government offensive saw troops capture several villages in the area, but it stalled after a rebel counterattack and stormy weather.

The current offensive is one of several the government has launched since Russian strikes began on September 30.

More than 260,000 people have been killed in Syria since the conflict began with anti-government protests in March 2011.
Source :AFP