The death toll from a massive explosion that struck a convoy of evacuees on the outskirts of Syria's Aleppo city rose to 112, a British war monitor said on Sunday.On Saturday, the blast, carried out by a suicide bomber driving a booby-trapped potato truck, struck a line of coaches carrying evacuated citizens through a checkpoint in rebel-held Rashidin as they were transported from the besieged, pro-government towns of Kefraya and Foah in Idlib province, Efe news quoted the Syrian Observatory of Human Rights (SOHR) as saying.The blast occurred at a time when the Syrian government was implementing an internationally-brokered evacuation deal, reached between the rebels and the government under the supervision of Iran, Turkey and Qatar, designed to secure from the two towns as well as Zabadani and Madaya, near the capital Damascus.In return, the government would allow rebels and their families to leave the rebel-held towns of Madaya and Zabadani in northern Damascus to reach Idlib, Xinhua news agency reported.The evacuation started on Friday, with 5,000 Shias leaving Kafaraya and Foah, and 2,300 rebels and their families leaving the town of Madaya as first batches.The people reached the rebel-held town of Rashideen while the rebels reached the government-controlled Ramouseh crossing in Aleppo. Some 3,000 people are still in the two towns waiting to evacuate.Once they are out, both towns will be completely emptied of any population, and the rebels will take over, after besieging the towns for years.