UNITED NATIONS - More than 5,000 people have been killed in the ongoing violence in Syria, Navi Pillay, UN high commissioner for human rights said here Monday.

Pillay made the statement to the press outside the chambers of the UN Security Council, after briefing the 15-nation council on the situation in the Middle East, including Syria.

"It is rather shocking that when I reported to the Security Council on the 18th of August, I reported that there were 2,000 civilians killed," she said. "Today I've reported that the figure exceeds 5,000 and the number of children killed is more than 300."

Tensions in Syria began in March when protesters took to the streets to call for the ouster of President Bashar Assad. The situation has since escalated, and Syrian security forces have been accused of firing on innocent protesters, reports said.

Syria has, from the beginning, blamed armed terrorist groups backed by a foreign conspiracy for being behind the turmoil with the aim of toppling the government of President Assad and replacing it with an Islamic rule.

On Wednesday, Assad blamed the violence in Syria on criminals, religious extremists and terrorists sympathetic to al-Qaida. He claimed that they are mixed with peaceful demonstrators.  

Pillay said thousands of Syrians have been put in detention centers by the government, where some experienced torture. Other Syrians have been displaced from their homes.

"These are the conditions and it was all taken very seriously by the members of the Security Council and every one of them said that this level of violence has to stop," Pillay said.

The Syrian government has repeatedly denied that its forces deliberately kill anti-government protesters, saying armed groups of the opposition are responsible for the bloodshed.

Pillay has recommended International Criminal Court (ICC) action on Syria.

Also on Monday, Bashar al-Ja'afari, the Syrian permanent representative to the UN, told reporters that his government, since the start of the political crisis in the Middle East country about eight months ago, has written 16 letters to the UN secretary-general, the president of the Security Council, the director-general of the UN Children's Fund (UNICEF), and the UN high commissioner for human rights.

The Syrian ambassador, who took out the letters from his files and showed them to the press, said the information offered by his government was not included in Pillay's briefing at the Security Council.  

"She was speaking on behalf of the (Syrian ) defectors," he said, referring to what was missed in the council briefing by Pillay about the violence from the armed opposition.