By Stephanie Nebehay
GENEVA (Reuters) - More than 2,200 people have been killed in Syria in the five-month-old crackdown by Syrian forces on anti-government protesters, the United Nations High Commissioner for Human Rights Navi Pillay said on Monday.
"The military and security forces continue to employ excessive force, including heavy artillery, to quell peaceful demonstrations and regain control over the residents of various cities," Pillay told the U.N. Human Rights Council, where Syria was in the dock.
"I wish to use this opportunity to once again call on the Syrian Government to immediately and fully halt its crackdown on peaceful protests and ensure the immediate and unconditional release of all people detained for their participation in peaceful demonstrations."
U.S. envoy Eileen Chamberlain Donahoe said the urgent session, the Geneva forum's second on Syria since April, underscored the growing international isolation of President Bashar al-Assad.
Syria's ambassador Faysal Khabbaz Hamoui rejected U.N. allegations that Syrian forces had committed crimes against humanity and accused "large states" of carrying out a misleading campaign to weaken his government, which he said was carrying out political reforms.
Khabbaz Hamoui said Damascus was willing to allow U.N. investigators into the country as soon as a Syrian judicial commission had completed its work.
"It is the first we have heard of this offer," U.N. human rights spokesman Rupert Colville told Reuters.
The United States, the European Union and Arab nations want to set up an international inquiry into atrocities by Syrian government forces.
CRIMES AGAINST HUMANITY
An initial United Nations investigation, whose results were issued last week, said the government's five-month crackdown on opposition demonstrators -- marked by killings, disappearances and torture -- might amount to crimes against humanity.
The team was not allowed into Syria but based their report on numerous interviews with victims and witnesses.
"We have credible allegations, documented evidence, that Assad has used tanks, machineguns, grenades and snipers against peaceful protesters and human rights defenders. Innocent civilians are being massacred," U.S. ambassador Eileen Chamberlain Donahoe told reporters in Geneva on Monday.
Later, in a speech, Donahoe said: "The United States deplores Assad's campaign of ever-increasing brutality and terror against unarmed innocents, which may amount to crimes against humanity."
Assad's forces shot dead two people in Syria on Monday, activists there said, hours after he dismissed Western calls to step down and warned that any military action against his country would backfire.
U.S. President Barack Obama has called for Assad to step down.
A draft resolution presented by some 25 council members, including all four Arab members (Jordan, Kuwait, Qatar and Saudi Arabia) as well as non-member Tunisia, would set up an international commission of inquiry on alleged crimes against humanity.
It would report back by the end of November and its findings would be sent to the U.N. Secretary-General and "relevant bodies."
Syrian envoy Khabbaz Hamoui warned that adoption of the resolution would be a "message of violence which will only cause the crisis to lengthen and cause more instability."
Syrian activists want prosecutions by the International Criminal Court (ICC) and hope the Human Rights Council will recommend the court's involvement to the U.N. Security Council. The Rights Council cannot itself authorize ICC involvement.
Investigators from the office of Pillay, a former U.N. war crimes judge, say they have a confidential list of 50 alleged perpetrators.
Radwan Ziadeh, an exiled Syrian activist who is director of the Damascus Center for Human Rights Studies, has been in Geneva for several days lobbying delegations for support.
"We need to put more pressure on the Security Council to refer Syria to the ICC for crimes against humanity which have been documented," he told Reuters.
China, Cuba and Russia are among countries wanting to remove the reference to crimes against humanity from the draft resolution, in exchange for joining a consensus, he said.
The United States supports accountability for the atrocities against the Syrian people, but the mechanism is still to be defined, U.S. envoy Donahoe told reporters.
(Reporting by Stephanie Nebehay; editing by Andrew Roche)