U.N. High Commissioner for Human Rights Navi Pillay said Friday she's seen video taken by rebel forces suggesting government soldiers were executed during a July melee in Khan al-Assal.
She said videos posted on the Internet show Syrian Red Crescent workers collecting the bodies while others show dead soldiers scattered in the streets with gunshot wounds to the head.
"Based on the analysis by my team to date, we believe armed opposition groups in one incident -- documented by a video -- executed at least 30 individuals, the majority of whom appeared to be soldiers," Pillay said in a statement.
She said the allegations are further reason for the government to allow her agency and members of an independent commission of inquiry to visit Syria to investigate the violence.
Both sides of the fighting in Syria are suspected of committing war crimes. Russian authorities in March accused rebel forces of using sarin nerve gas during an early battle at Khan al-Assal, an Aleppo suburb.
Syrian President Bashar Assad said much of the criticism of his regime has been lopsided. He met with troops Friday in Damascus to express support for their resilience.
"Our motto has always been martyrdom or victory, but, since the outbreak of the battles, our motto became victory," he was quoted by the official Syrian Arab News Agency as saying. "Martyrdom is a destiny."