There has been no let up in violence in Syria with parts of the capital, Damascus, under fire for a second day, activists have said.
The military offensive on Monday reportedly continued to batter several neighbourhoods in the capital, including Tadamon, Kfar Souseh, Nahr Aisha and Sidi Qadad.
"The regular army fired mortar rounds into several suburbs", where members of the Free Syrian Army, the main armed oppositiong group mainly composed of military defectors, are entrenched, said Rami Abdel Rahman, head of the Syrian Observatory for Human Rights, the UK-based activist group.
"(It has) never been this intense," Abdel Rahman told reporters.
"The security forces are attempting to take control of these neighbourhoods but so far they have not succeeded," he added.
The main political opposition group, the Syrian National Council (SNC), hailed the FSA fighting army troops in the capital, accusing the regime of having transformed opposition neighbourhoods into "a battlefield".
"The revolution is spreading and has tightened the noose around the regime in zones where it thought it was beyond the anger of the people," SNC spokesman Georges Sabra said.
The Local Co-ordination Committees activist network said plumes of black smoke were billowing out of Tadamon and that loud explosions were heard in Nahr Aisha.
The Observatory and the LCC both said more than 50 people were killed across the country on Sunday.
The government remains defiant, insisting it is defending its people and sovereignty.