Syrian army tanks have shelled the old quarter of Deraa, the southern city at the heart of the six-week-old uprising, said a witness on Sunday.
Deraa has been without water, fuel or electricity since Monday, when the regime sent in troops backed by tanks and snipers to crush protests seeking an end to President Bashar al-Assad’s authoritarian rule.
Tanks and armoured personnel vehicles have cut off neighbourhoods, and snipers on rooftops throughout the city have kept residents pinned in their homes.
Other areas of the country have also come under military control, but Deraa has come under the most serious stranglehold as the death toll has soared to 535.
Tanks fired shells into the heart of Deraa's ancient Roman quarter, said a resident who lives on the outskirts of the city.
He said he could identify the weaponry because he was a former soldier.
Men were forbidden to leave their homes but women were allowed out in the early morning to search for bread, he said, speaking on condition of anonymity for fear that Syrian forces would identify him.
Residents have responded to the crackdown by shouting the traditional rallying cry “God is great!” from their homes over the past several evenings, he said. “Our houses are close to each other, so even though we can't go outside, we stand by the windows and chant it. Our neighbours can hear us and they respond.”
The witness's account could not be independently verified. Syria has banned nearly all foreign media and restricted access to trouble spots, making it almost impossible to confirm the dramatic events shaking one of the most authoritarian regimes in the Arab world.
On Saturday, Syrian troops killed four people while storming a mosque that has become a focal point for protesters in Deraa, and security forces in Damascus kept dozens of women from marching on parliament to urge Assad to end his crackdown.