The conflict in Syria was effectively declared a civil war by the Red Cross on Sunday, as the "most intense" fighting since the start of the uprising was reported in Damascus.
The Red Cross had previously designated Idlib, Homs and Hama as war zones, but the change in status means international humanitarian law applies wherever fighting occurs throughout the country
Combatants will now be officially subject to the Geneva Conventions, and will be more exposed to war crimes prosecutions, after the ICRC declared that the conflict was a "non-international armed conflict", or in lay terms a civil war.
Sean Maguire, a spokesman for the ICRC, said that both sides would be reminded of their obligations "to protect civilians from fighting, treat the wounded and sick without discrimination".
The categorisation was made after the ICRC determined that the armed opposition to Bashar al-Assad's regime had reached a sufficient level of organisation and capability.
The Syrian Observatory for Human Rights reported heavy clashes in the capital in what was described as the "most intense" fighting there since the start of the anti-regime revolt in Syria.
"The regular army fired mortar rounds into several suburbs" where rebels of the Free Syrian Army are entrenched, said Rami Abdel Rahman, head of the Syrian Observatory for Human Rights. "They have never been this intense."
Kofi Annan, the international envoy of Syria, and Ban Ki-Moon, the UN secretary general, set off on a trip to Russia and China on Monday in a bid to persuade them to back tougher action against Bashar al-Assad, the Syrian president, but hopes for a breakthrough are slender.
The Syrian government went on the offensive yesterday by attempting to claim a propaganda victory after UN observers called into question opposition claims of a civilian massacre in the village of Tremseh.
Local activists had accused regime forces of slaughtering as many as 220 civilians in what would have been the worst massacre of the 16-month uprising against Mr Assad.
Although a team of monitors that reached the scene encountered scenes of heavy destruction and found evidence of mass fatalities, they concluded that the vast majority of the dead were rebels or opposition activists.
Their findings were swiftly trumpeted by the Assad regime, which accused Western leaders and Mr Annan of rushing to draw fallacious conclusions.
But while the observers' report suggested that the government's narrative was closer to reality than the opposition's, the events that unfolded in Tremseh last Thursday remain murky.
Nor was the regime's position entirely vindicated. The UN stood by its accusation that government forces had used tanks and helicopter gunships in breach of a pledge made by Mr Assad a week ago not to use heavy weapons.
Reaching the village 48 hours after the killings, the observers spoke of encountering scenes of devastation and seeing chilling traces of the ferocity of the government's onslaught amid the ruins.
"There were pools of blood and blood spatters in rooms of several homes together with bullet cases," said Sausan Ghosheh, a spokesman for the monitoring team.
"A wide range of weapons were used, including artillery, mortars and small arms."
The findings appeared to suggest that a number of the victims were shot at close range, echoing opposition claims of execution-style killings carried out by the pro-Assad Shabiha militia, whose ranks are largely drawn from president's Alawite minority.
But the observers also reported that the attack appeared to target "specific groups and houses, mainly of army defectors and activists" -- a significant departure from the narrative of some opposition activists.
Tremseh lies along the same sectarian fault line as two other Sunni villages – Howl and Qubeir – whose inhabitants were allegedly massacred by army soldiers and militiamen from surrounding Alawite communities.
In both cases, photographic evidence was produced to show a large number of women and children among the dead. But video footage from Tremseh indicated that nearly all the dead were men of fighting age.
If, as now seems likely, the killings were the result of a lopsided battle, they would represent one of the most catastrophic rebel defeats of the campaign.
Opposition sources conceded that most of the dead were fighters and confirmed that the battle had been triggered by a rebel ambush on an army convoy.
But they claimed that few of the dead were formal rebels, saying that most were male inhabitants of the village who had taken up arms to prevent an Alawite attempt to "cleanse" Tremseh.
Lacking the sophisticated communications equipment that most rebels in the Free Syrian Army have, the rebels were unable to call for reinforcements resulting in a heavily one-sided battle, one activist said.
The death toll remained in dispute, with the government saying that 37 opposition fighters and two civilians were killed. Opposition activists said that between 100 and 150 died, but conceded that they only knew of "at least seven" civilian fatalities.
Presented with a rare opportunity to portray itself as misrepresented, the Syrian government launched a public relations offensive to absolve itself of guilt.
"What happened in Tremseh was a military operation, not as massacre," Jihad Makdissi, the Syrian foreign ministry's spokesman, told a press conference."
He also furiously denounced a letter written by Mr Annan to the United Nations Security Council that urged members to unite in action against the regime for its use of heavy weaponry in Tremseh. A similarly worded letter was sent to the Syrian foreign ministry.
"The least that can be said about this letter about what happened in Tremseh is that it did not rely on facts," Mr Makdissi said. "As diplomatically as possible, we say that this letter was very rushed."
The dispute over Tremseh is likely to complicate international efforts to resolve the Syrian crisis, with Russia almost certain to seize on it as evidence that the opposition, rather than the regime, is responsible for most of the bloodshed.
The mandate for the 300-man observer mission to Syria is due to expire on Friday with no sign of an end to international divisions.
Russia wants the mandate to be renewed for a further three months. But it is resisting Western efforts to bolster it with a Security Council resolution threatening the Assad regime with sanctions if it fails to take steps to end the violence and form a transitional government with the opposition.
Meanwhile, the president of Syria's main opposition group, the Syrian National Council, stepped up pressure on America to take action by accusing President Barack Obama of stalling so as not to jeopardise his November re-election prospects.
"We cannot understand that a superpower ignores the killing of tens of thousands of Syrian civilians because of an election campaign that a president may win or lose," Abdelbasset Sayda told CNN.
BLOB: A Russian ship, making a second attempt to deliver arms to Syria mysteriously returned to port yesterday. The MV Alaed was prevented from making its delivery of refurbished attack helicopters in June after Britain ensured that its insurance cover was withdrawn.
Please follow Military & Defense on Twitter and Facebook.