Beirut: More than 100 people were killed April 14 a car bomb hit buses evacuating residents from a town in northern Syria.

The attack served as a bloody reminder of the human stakes for regional powers as they broker a complex population swap, moving some 30,000 Syrians between government and rebel-held territory. The area had come under the rebels more than two years ago.

Syrian state television showed bodies on the ground, charred vehicles packed with their passengers’ possessions.

The buses had left the northern town of Fouaa on April 13 as part of a long-awaited first phase of that agreement. Those on board had spent years under siege by extremist rebels, living in fear and without access to regular food or medicine, report the Washington Post.

The White Helmets rescue group said its volunteers had recovered more than 100 bodies from the wreckage, and that another 55 people had been injured. The death toll was expected to rise.

The dead included civilians as well as local rebel fighters.

There was no immediate claim of responsibility for the blast, and its implications for the broader transfer deal were unclear.

Overseen by Qatar and Iran, the negotiations had negligible input from the Syrian government, underscoring the extent to which President Bashar al-Assad has lost control in certain areas.

The population shift is an attempt to alleviate the hardships of residents in towns under siege by both rebel and government forces.

Each side has used the civilians it surrounded as bargaining chips to gain leverage over the other.

Some 2.3 million Syrians lived under complete siege or in areas at risk, according to Siege Watch, a Washington-based monitoring group.

Opposition officials have accused the Syrian government and its Iranian allies of using siege tactics to force demographic changes across the country, mostly along sectarian lines.

The mostly Shiite towns of Fouaa and Kefraya have been reliant on government airdrops since rebel forces cut their supply lines in May 2015.