The Syrian capital of Damascus is seeing some of its heaviest fighting to date since the uprising against Syrian President Bashar al-Assad erupted over a year ago. Heavy weaponry including tanks and mortar fire has reportedly been used in areas to the city’s south. The intensified clashes have prompted the International Committee of the Red Cross to join the United Nations in describing the conflict in Syria as a “civil war.” The Red Cross had previously kept its assessment to a handful of flashpoint areas but now says the violence is nationwide. The U.N. observer mission has confirmed heavy weaponry was used last week in the village of Tremseh, where pro-Assad forces were accused of massacring more than 100 civilians. U.N. spokesperson Sausan Ghosheh announced the observers’ findings earlier today.

Sausan Ghosheh: “In this attack, there was use of heavy weapons on population centers. Our observers confirmed the use of direct and indirect weapons, including artillery, mortar shells and small arms. And the accounts of 27 that we interviewed, the consistent account all indicated that the attack started at five o’clock in the morning via shelling, and then ground forces went in.”

The Assad regime has denied carrying out a massacre in Tremseh, claiming it killed anti-government rebels.