Al-Jazeera Video: Fighting rages in the southern Syrian town of Herak

"In Syria, government forces are shelling several cities. But it's the capital, Damascus, that's the scene of the worst fighting.

Troops are attacking by land and air, trying to crack down on what they call 'terrorist elements' in the capital and surrounding areas.

Damascus residents say the shelling has been constant.

Al Jazeera's Rula Amin reports from Beirut."