BEIRUT ¨C Syria¡¯s army seized an area north of Aleppo on Sunday and killed insurgents as fierce battles raged over the strategic territory, a group monitoring the war and state media reported.

Syria¡¯s second city is at the heart of clashes between pro-government forces and a range of insurgents, including al-Qaida¡¯s Syria wing, Islamist brigades and Western-backed rebels.

The United Nations Syria envoy, Staffan de Mistura, is seeking a local cease-fire in Aleppo to allow badly needed humanitarian assistance into the divided northern city.

Insurgent-held districts have been flattened by Syrian air force bombardments, including barrel bombs ¡ª crude explosive devices packed with shrapnel and nails.

Pro-government forces captured an area east of al-Malah farms outside Aleppo and are now aiming to secure parts in the west and cut off insurgent supply lines into the city, the Britain-based Syrian Observatory for Human Rights said.

It said 34 fighters from Islamist groups, including al-Qaida¡¯s Nusra Front, were killed when Syria¡¯s army attacked their positions with backup from local and foreign militias. It added that there were also battles south and east of the city.

Syria¡¯s state news agency said the army was tightening its ¡°grip on terrorists in Aleppo after new advances.¡±

It said pro-government forces had captured all of the al-Malah area as well as areas south and west of Handarat town in the countryside and reported that a ¡°huge number¡± of enemy fighters had been killed.

Western diplomats have voiced concerns about the cease-fire plan, saying it could be used by the government to take full control of the city and force rebels to surrender, as it did through a previous initiative in the central city of Homs, and then direct its forces elsewhere.

The U.N.¡¯s de Mistura has defended the plan, saying that opposition forces backed the idea and has warned the fall of the city could create an additional 400,000 refugees.