Shattered streets of Homs belie Assad's promises of peace

As President Bashar al-Assad's promise that he will abide by a ceasefire was met with scepticism yesterday, evidence emerged of the utter devastation wrought by his forces during the fierce bombardment of opposition forces in the central city of Homs.

Photographs showed buildings reduced to rubble, charred homes where families once lived and cars turned into lumps of twisted metal by the ferocity of the firepower unleashed in an offensive against rebels beginning in early February. Despite the regime's promises, the devastation in Homs and elsewhere looks set to continue, as Mr Assad's troops showed no let up yesterday in their ruthless campaign of bombarding rebel strongholds with just hours to go before a final deadline.

The UN-Arab League envoy for Syria, Kofi Annan, who is spearheading diplomatic efforts to bring an end to the bloodshed, said he had "received reassurances" from Damascus that a truce – due to begin at 6am today – would be respected and Syria's official news agency said the army would stop operations. But a Tuesday deadline for troops to begin withdrawing from towns and villages came and went with little sign that the regime was meeting its commitments.

"We have had positive answers from them and have also approached governments with influence to ensure that all parties respect the ceasefire," Mr Annan said during a visit to Tehran, where he is trying to garner support. He said he expected an "improved situation" on the ground today.

But shortly after he spoke, 20 Syrian army tanks were reported to have rolled into the centre of Hama and plumes of smoke could be seen rising over the shell-wracked city of Homs, where activists said the neighbourhood of Khalidya suffered much of the fresh assault.

Rastan, which lies between the two opposition hubs, also came under heavy shelling, activists said. At least 30 people were confirmed dead by the Local Co-ordination Committees by yesterday evening, after triple-digit death tolls every day this week.

Abu Rami, a Homs resident, said he counted more than 20 explosions in just one hour. "The only important thing for the regime is to gain more time to end this uprising by shelling and bombing," he said. "When we reach the deadline, Assad will say that that the opposition haven't laid down their guns, so he can continue his shelling and violence. Kofi Annan's initiative is already dead."

Under the plan the onus was on Syrian forces to withdraw first and rebels to follow their lead, with both sides ceasing fire by today. If Mr Annan's plan collapses, the door will close on the only initiative that has gained the backing of Syria's allies Russia and China, which have hamstrung UN Security Council resolutions, and Mr Assad's opponents will have to go back to the drawing board. David Cameron yesterday warned Mr Assad that he faced a "day of reckoning" for the "savagery" he was showing towards his opponents. Mr Cameron, who spoke to Mr Annan yesterday, called for a new UN Security Council resolution on Syria to give fresh impetus to efforts to end the bloodshed. He accused the Syrian regime of continuing to turn its weapons against dissidents 11 days after it promised to stop the killing.

"Far from fulfilling their commitments, the regime is cynically exploiting the window of diplomatic negotiations to crack down even harder on its own people," Mr Cameron said during a visit to Indonesia. "It is clear the world needs to redouble its effort to stop the killing and intensify our support to those who oppose Assad's savagery. This is a decisive moment; the United Nations Security Council now has a clear responsibility to throw its full weight behind Kofi Annan's plan and to insist it is implemented.

"Together we must ensure there is a day of reckoning for Assad's crimes."