Navi Pillay spoke in Geneva, Switzerland at a special session of the U.N. Human Rights Council, which met to discuss allegations of human rights violations in Syria.

The meeting comes after the United Nations sent a humanitarian mission to Syria this weekend to look for effects of President Bashar al-Assad's protest crackdown.

Pillay said that more than 2,200 people have been killed in the crackdown so far, with more than 350 people reportedly killed since the start of Ramadan.

Meanwhile in Syria, the Syrian Observatory for Human Rights reported new deaths in a continuing crackdown on pro-reform demonstrators.

Two people were killed and four wounded on August 22 in the city of Mesyaf in Hama province when regime supporters opened fire, the London-based activist group said.

It also said that at least three people were killed and five injured in Homs, when gunmen opened fire on demonstrators participating in a protest timed to coincide with the UN delegation's visit.