Opposition activists said Tuesday that forces loyal to Bashar al-Assad have stepped up their attacks on anti-regime militants as a final blow before next week's planned ceasefire, to which the government agreed yesterday. Syria's regime sent reinforcements into rebel areas despite a truce pledge, as the UN said it was rushing a team to Damascus to pave the way for peace monitors. The surge in violence on Tuesday killed at least 38 people, including 25 civilians, mostly in north and central Syria, and saw a string of arson attacks on homes, activists and monitors said. It came a day after peace envoy Kofi Annan told the UN Security Council that President Bashar al-Assad had given assurances he would "immediately" start pulling back his forces and complete a military withdrawal from urban areas by April 10. The United States accused Assad of failing to honour his pledged troop withdrawal, as monitors reported heavy fighting in opposition strongholds in the southern region of Daraa, the central city of Homs, northwestern Idlib province and near the capital. The Syrian Observatory for Human Rights has charged that the army is torching and looting rebel houses across the country in a campaign that could amount to crimes against humanity. Dozens of armoured personnel carriers arrived in Dael, a town in Daraa province where the uprising against Assad began in March 2011, as well as in Zabadani, a bastion of the rebellion near the border with Lebanon.