At least 126 people were killed in Syria last Saturday and 68 of which are children.
Apparently, the buses that transport the evacuees were attacked with a vehicle that carries explosives nearby Aleppo.
According to BBC, the UK-based Syrian Observatory for Human Rights monitoring group claimed that most of the evacuees who died were aid workers and rebel soldiers.
Aside from the casualties, the attack also left many injured civilians. The said incident had left trails of body, shattered buses, and cars on fire.
The evacuees were brought from Foah and Kefraya and as of now, no group has claimed for the attack.
It happened at around 15:30 Syria time (12:30 GMT) at Rashidin, at the checkpoint where the evacuees were handed over. The evacuation is a part of the "four towns" deal that allows many civilians to leave. It applies to Foah, Kefraya, Madaya and Zabadani.
Apparently, a vehicle that contains foods had started attracting people especially kids with its crisps. Soon after, an explosion happened.
Lina Sinjab of BBC Middle East, however, was skeptical about it since no such vehicle could have reached the area sans the consent of the government.
Meanwhile, there were proofs linking the terrorists to the attack.
The bus bombing that killed over a hundred people was called a "vile attack on fleeing refugees" by Pope Francis on his Easter Sunday talk.
"May [God] sustain the efforts of those who are actively working to bring comfort and relief to the civilian population in beloved Syria, who are greatly suffering from a war that does not cease to sow horror and death," the Pope said.
Meanwhile, a separate incident in the country's capital, Damascus, has left several people injured. At least three shells, which are blamed to works of the terrorists, have landed nearby central Umayyad Square and the pro-government media networks.