The United Nations mission in Syria says its observers have witnessed government fighter jets opening fire on Aleppo, the country's largest city..

The United Nations mission in Syria says its observers have witnessed government fighter jets opening fire on Aleppo, the country’s largest city..

In a briefing on Wednesday, mission spokeswoman Sausan Ghosheh also said the U.N. had confirmation that the rebels now have heavy weapons of their own, including tanks.

Ghosheh expressed concern over the situation in the northern city of Aleppo, where rebels have been battling government forces for the past 12 days.

She described “heavy use of heavy weapons, including tanks, helicopters, heavy machine guns, as well as artillery.”