|Activists reported 'terrifying explosions' in the flashpoint central city of Homs for a 20th straight day [Reuters]
A United Nations human rights investigation has found that Syria had "manifestly failed" to protect its own people.
The report, prepared by the UN-appointed Independent International Commission of Inquiry on Syria, came as deadly violence continued across the country and Arab and Western states prepared to discuss a proposal to get humanitarian aid into areas under military assault.
The UN panel said on Thursday that it had submitted a list of Syrian military and political officials suspected of crimes against humanity to Navi Pillay, the UN's top human rights official.
It is believed the list could go as high as Bashar al Assad, the Syrian president, whose security crackdown has left an estimated 8,000 people dead since protests erupted against his government in March 2011.
The report, commissioned by the UN Human Rights Council, cites numerous atrocities, including the shooting and killing of civilians, shelling residential areas, and torturing wounded protesters in hospital.
It also accuses the opposition of carrying out murder, torture and abductions, but says those were "not comparable in scale and organisation to those carried out by the state".
Demand for accountability
The investigators have deposited with the High Commissioner [for Human Rights] a comprehensive database containing all evidence collected," the panel said.
"Consistent with its mandate, the commission endeavoured, where possible, to identify those responsible with a view to ensuring that perpetrators of violations, including those that may constitute crimes against humanity, are held accountable."
In-depth coverage of escalating violence across Syria
The three-member commission recommended the initiation of an inclusive political dialogue, bringing together the government and opposition groups.
Both sides should "negotiate an end to the violence, to ensure respect for human rights and to address the legitimate demands of the Syrian people", it said.
The UN criticism of the Syrian government came as Hillary Clinton, the US secretary of state, was reported to have discussed the "unified humanitarian proposal" with counterparts on the sidelines of an international conference on Somalia in London.
Speaking on conditions of anonymity, a US administration official said that the proposal would be discussed in the Friends of Syria meeting to be held in the Tunisian capital on Friday.
The Friends of Syria group brings together the US, its European allies and Arab states working to end the turmoil in the country.
"I think one of the things you are going to see coming out of the meeting tomorrow are concrete proposals" on the supply of aid "within days”, the US official said.
"The challenge is on the Syrian regime to respond to this.”
The Tunis meeting will be the group's first since it was created in response to a joint veto by China and Russia of a UN Security Council resolution condemning Assad's crackdown.
On the ground, meanwhile, opposition activists reported up to 24 deaths in central city of Hama and spoke of "terrifying explosions" in Homs, which has been under military assault for a 20th straight day.
Anita McNaught reports from Antakya, Turkey, where the Syrian uprising is fuelling local tensions
Thursday's bombardment centred on the Bab Amr neighbourhood, where Marie Colvin, a veteran US reporter, and Remi Ochlik, a French photojournalist, and scores of others were killed the previous day.
Hadi al-Abdallah, a Homs-based activist, told the AFP news agency the international outcry over the deaths appeared only to have strengthened the government’s determination to eliminate all opposition in the city.
"The more the condemnations pile on, the heavier the bombing becomes," he said.
Abdullah said there was evidence that the makeshift media centre where the journalists were killed was deliberately targeted by government forces.
"We are sure that the centre was targeted, because 11 rockets struck in and around it," he said.
"The regime forces intercepted a transmission signal."
The Syrian government made no effort to deny that its forces had fired the lethal rounds.
"We reject statements holding Syria responsible for the deaths of journalists who sneaked into its territory at their own risk," according to a foreign ministry statement read out on state television.
The ministry urged journalists to "respect laws of journalistic work in Syria and avoid breaking the law by entering the country illegally to reach trouble-hit areas that are unsafe".