Updated

The U.N.'s human rights office said Friday that activists' reports of up to 850 people being killed during anti-government protests in Syria are realistic.

A spokesman for the U.N. High Commissioner for Human Rights said government forces appeared to have continued their violent crackdown on protesters by shelling parts of the city of Homs — the country’s third largest-city and a center of the uprising — on Wednesday.

Reports from human rights groups "suggest that somewhere between 700 and 850 people have been killed since the start of the protests on March 15, and thousands of other people have reportedly been arrested," spokesman Rupert Colville told reporters in Geneva.

"We cannot verify these numbers for sure, but believe they are likely to be close to reality," he said.

The global body is preparing to send a high-level fact finding team to Syria as soon as it receives government permission, Colville added.

The team, led by Deputy High Commissioner for Human Rights Kyung-wha Kang, will investigate allegations that security forces indiscriminately killed and detained civilians in several cities during anti-government protesters.