Syrian activists say clashes between government forces and rebels are continuing in Aleppo, as the military presses on with an assault on opposition-held areas of the country's largest city.

The Local Coordination Committees and the Syrian Observatory for Human Rights reported fighting Thursday in several districts of Aleppo.

The Syrian military launched a two-pronged attack on the city Wednesday, with jets and helicopters bombing from overhead while ground forces targeted rebel positions.

Meanwhile, Syrian ally Iran is trying to advance a solution to the crisis with talks Thursday in Tehran.

Foreign Minister Ali Dakar Salehi says Iran is hosting a meeting of countries committed to implementing an immediate cease-fire, sending humanitarian aid to Syria and preparing for dialogue.

Russia is sending its ambassador to Iran to the talks, but it is unclear which other nations may take part.