Peace envoy Kofi Annan said yesterday he was shocked by mounting violence in Syria ahead of a UN deadline for regime forces to cease fire, as Damascus said its troops will not withdraw from protest hubs without written guarantees.

“I am shocked by recent reports of a surge in violence and atrocities in several towns and villages in Syria, resulting in alarming levels of casualties, refugees and displaced persons, in violation of assurances given to me,” Mr Annan said in a statement.

It came as Syria’s main opposition group urged UN intervention after one of the deadliest days in a year saw nearly 130 people killed, mostly civilians. As tomorrow’s deadline loomed for regime forces to cease fire and pull back from rebel cities, the foreign ministry said it had not been given assurances that “armed terrorist groups” would also put down their guns.

“To say that Syria will pull back its forces from towns on April 10 is inaccurate, Kofi Annan having not yet presented written guarantees on the acceptance by armed terrorist groups of a halt to all violence,” it said.

On Thursday, the UN Security Council formally endorsed the deadline, but Damascus said a day later the number of “terrorist acts” has risen since the deal was agreed with the UN and Arab League envoy. “Mr Annan has not submitted written guarantees from the governments of Qatar, Saudi Arabia and Turkey on stopping their funding to terrorist groups,” the ministry added of its northern neighbour and strongest critics in the Arab world.

Mr Annan’s peace plan foresees the withdrawal of the Syrian army from protest cities tomorrow, with a complete end to fighting 48 hours later.

The ministry said that when Mr Annan met President Bashar al-Assad in Damascus, the former UN chief “said he would work to stop the violence, disarm armed groups... initiate a comprehensive national dialogue with opposition movements. It is this principle on which Syria accepted Annan’s mission and his six-point plan.”