A Syrian opposition monitoring group and a TV station are reporting that government forces have captured farms near the northern city of Aleppo, tightening the noose around the only gateway leading to rebel-held parts of the city.

The Britain-based Syrian Observatory for Human Rights says government forces now control half the Mallah farms on the northeastern edge of Aleppo, Syria's largest city and once commercial center.

The Beirut-based Pan Arab TV Al-Mayadeen says with Tuesday's capture of large parts of Mallah farms, troops now can fire upon and close the Castello road that links rebel-held parts of Aleppo with the rest of the country.

State media aired footage from the area, showing Syrian army tanks and artillery pounding Mallah farms. Aleppo has seen some of Syria's worst fighting this year.