Footage filmed in Syria's largest city shows heavy gunfire as rebels and government forces battle for control of the airport, and President Assad appears publicly for the first time in six weeks.

Please wait while this video loads. If it doesn't load after a few seconds you may need to have Adobe Flash installed.

The video, shot on Friday, shows opposition fighters firing rocket-propelled grenades in areas leading to the airport.

Foreign journalists said President Bashar al-Assad's forces responded with helicopter gunfire and mortars.

Families were seen fleeing Aleppo as the fighting intensified.

Syria's state news agency said that "armed terrorist groups" - regime shorthand for the rebels - had been pushed from both sides of the airport by government troops.

Tens of thousands flee Aleppo

It was the first official acknowledgement that fighting was taking place close to a strategic gateway to the country's largest city.

The report did not specify whether it meant the international airport or the adjacent military airfield.

Tens of thousands of civilians have now fled Aleppo, which has major symbolic and strategic value. It is the main hub of northern Syria and close to the northern countryside where rebels organise and bring in supplies from Turkey.

Rebels are trying to take control the city centre, which would further undermine government claims that its professional army can easily quash opposition forces.

Please wait while this video loads. If it doesn't load after a few seconds you may need to have Adobe Flash installed.

Eid prayers

Assad appeared in public today for the first time since July when four security officials were killed in a bomb blast. State television showed him performing Eid prayers in a Damascus mosque.

Assad sat cross-legged during a sermon describing Syria as the victim of a conspiracy hatched by the United States, Israel, the West and Arab states. He was joined by his prime minister but not his vice president, Farouk al-Shara, whose reported defection has been denied by the government.

The 17-month-old conflict between Assad's regime and rebels trying to bring him down has left some 20,000 people dead, according to estimates by anti-Assad activists.

The escalating fight has in the past two months turned to battles in the former Assad strongholds of Damascus and Aleppo.

Rebels have managed to keep fighting in both cities despite facing overwhelming regime firepower.

Reports: 'UK intelligence given to rebels'

The Sunday Times reported today that Britain is passing military intelligence to the rebels.

The newspaper quotes an unnamed Syrian opposition official as saying that signals intelligence from UK sources is being passed on to Free Syrian Army fighters via Turkish and American intermediaries.

The official said intelligence about Syrian troop movements has helped the rebels launch devastating attacks on tropps loyal to Assad.