The 16-month Syrian crisis has essentially become a civil war, a Red Cross spokesman said Monday, meaning international humanitarian law would now apply "wherever hostilities take place."
The International Committee of the Red Cross officially describes the situation as a "non-international armed conflict" and does not use the term "civil war."
But spokesman Alexis Heeb said the group's legal term "appears in the Geneva Conventions to describe a civil war."
"What is new is the fact that in April ... we referred to three specific locations" of internal conflict, Heeb said. Now the ICRC says the internal strife is evident in other areas.
"Rather than to limit the non-international armed conflict, we say that IHL (international humanitarian law) applies wherever hostilities take place," Heeb said.
Fresh hostilities erupted once again Monday, opposition activists said, as regime forces fired machine guns on civilians' houses in Aleppo.
In the beleaguered city of Homs, "several houses have been destroyed and other caught on fire" amid mortar and missile attacks, the opposition Local Coordination Committees of Syria said.
And the capital city of Damascus sustained another day of clashes between regime and rebel fighters, the LCC said.
The stakes are high for world leaders to agree on a plan for Syria, with reported death tolls soaring into the dozens or hundreds in recent days.
At least 72 people were killed Sunday in cities across the country, the LCC said.
The deaths included 11 people "martyred under torture in the regime's prisons," seven soldiers who defected, three women and six children, the group said.
Over the weekend, U.N. monitors visited the Syrian town of Tremseh, where opposition activists say more than 200 people were massacred on Thursday -- the deadliest day yet in the Syrian conflict.
A patrol found more than 50 houses burned or destroyed, and "pools of blood and brain matter were observed in a number of homes," the U.N. Supervision Mission in Syria said in a statement.
Twenty-seven local villagers offered a "consistent account," saying Syrian forces began by shelling the village in the early morning on Thursday, then followed with ground operations.
"According to those interviewed, the army was conducting house-to-house searches asking for men and their ID cards," the statement said.
"Numerous" people were then killed after their identification was checked, the villagers said, and some other men were taken from the village, it added.
"On the basis of some of the destruction observed in the town and the witness accounts, the attack appears targeted at army defectors and activists."
Since the Syrian crisis began in March 2011, the United Nations estimates more than 10,000 people have been killed in the violence; opposition activists say more than 15,000 have died.