Activists say Syrian government forces backed by Lebanon's Hezbollah fighters have captured two villages near the northern city of Aleppo, and will soon be able to besiege rebel-held neighborhoods in the country's largest city.

The Britain-based Syrian Observatory for Human Rights and Aleppo-based activist Amer Hassan say government forces were able to cut off the highway linking Aleppo with the Turkish border.

The Observatory's chief Rami Abdurrahman says government forces are also advancing toward two nearby Shiite villages that have been under siege for nearly two years.

Abdurrahman and Hassan say Tuesday's push by the government and Hezbollah is the biggest blow to rebels in the province in three years.

Aleppo, Syria's largest city and once commercial center, has been divided by neighborhood between government and opposition forces since mid-2012.