Free Syrian Army
The UK's Cameron will meet with his defense minister Wednesday to discuss having a no-fly zone in Syria, meanwhile France may start arming Syrian rebels, pictured here. Reuters

The U.N. and rights groups have condemned footage that allegedly depicts Syrian rebels shooting captured government troops, which may provide evidence of the commission of war crimes.

The killings reportedly took place after rebels gained control of several strategic army checkpoints on Thursday.

The footage, which was leaked online, shows Syrian soldiers allegedly being beaten by rebels before being shot, and it is believed that Islamist militant group the Al-Nusra Front was behind the killings, though no group has yet claimed responsibility, the BBC reported.

"It seems very likely that this is a war crime, another one," said the U.N. High Commissioner for Human Rights spokesman Navi Pillay.

Human rights organization Amnesty International also weighed in on the footage and condemned the extrajudicial executions.

"This shocking footage depicts a potential war crime in progress and demonstrates an utter disregard for international humanitarian law by the armed group in question," the organization said in a statement, the BBC reported.

The footage surfaced less than a day after U.S. Secretary of State Hillary Clinton warned against the incursion of extremist groups into rebel forces, which she described as an attempt to “hijack the Syrian revolution.”

Meanwhile, the Syrian government's warplanes continue to bomb rebel targets throughout the country.

Both the military and rebels have been accused of violating human rights over the course of the 19-month-old conflict, which the U.N. estimates has resulted in at least 20,000 deaths, including many civilian casualties.