More than 5,000 people have died in the nine-month-long Syrian uprising, U.N. human rights chief Navi Pillay said Monday.
Pillay, the U.N. High Commissioner for Human Rights, told reporters Monday that she told Security Council members of the dramatic increase in deaths during an afternoon briefing.
The death toll used by the U.N. in recent weeks has been around 4,000.
Pillay said she recommended that the council refer Syria to the International Criminal Court, the permanent war crimes tribunal, for investigation of possible crimes against humanity.
Pillay said that at least 300 children are among the dead, and there are thousands of people in detention.
She noted that the last time she briefed the council on Syria, in August, the death toll was at about 2,000.
U.S. Ambassador Susan Rice said Pillay's briefing "underscores the urgency of the present moment."
"Through condemnations issued by the U.N. General Assembly and Human Rights Council and bold steps taken by the Arab League and the Government of Turkey, international bodies are starting to match their severe disapproval of Syria's bloody crackdown with concrete steps to bring it to an end," Rice said. "It is past time for the U.N. Security Council to do the same."
The representatives of France, Britain, Portugal and Germany also said it was time for the council to take strong action on Syria.
"Obviously, we will consider a range of options when the issue comes back to the Security Council," British Ambassador Mark Lyall Grant said. "We will need to move in lockstep with the Arab League."
"Today, Navi Pillay placed Security Council members on notice of the scale of the tragedy unfolding in Syria," said Philippe Bolopion, U.N. director for Human Rights Watch.
"History will judge harshly those who still choose to look the other way," he said. "Inaction is not an option anymore."
Last month, Russia and China vetoed a Western-backed U.N. Security Council resolution condemning the bloodshed in Syria.
"The only way to resolve the situation in Syria is through a Syrian-led political process, and that means dialogue," Russian Ambassador Vitaly Churkin said.