With the dust of the Tremseh Massacre only beginning to settle and Damascus reportedly experiencing the fiercest fighting yet since the start of the long uprising in Syria, former Syrian ambassador Nawaf al-Fares is calling for military intervention.

Fares, who told CNN he was at the top of the Syrian regime before defecting last week, said Sunday that he supports military intervention because I know the nature of this regime, adding that the Alawite minority-dominated government of Bashar al-Assad will only go by force.

Although United Nations-Arab League envoy Kofi Annan continues to proclaim his six-point peace plan, which was ignored by Assad at its inception in April, fighting between the government and rebel forces seems to be headed in one direction. Residents and activists in Damascus told Reuters on Sunday that fighting in the capital is escalating, especially in the poor neighborhoods on the outskirts of the city, where rockets and heavy weaponry are reportedly being used.

The International Committee of the Red Cross also declared Sunday that the crisis in Syria should be considered a civil war after a battle in Tremseh appeared to be a repeat of the Houla massacre, in which more than 100 civilians were killed during a single night in May.

What happened in the last year during the holy revolution, all of the killing, the massacres, the refugees, and the declaration of war by Bashar al-Assad against the Syrian people, stopped any kind of hope for reform or real change, which had been promised previously by Bashar al-Assad, Fares said.

I tried during the last year and a half to convince the regime to change its treatment of the people. But I wasn't successful, so I decided to join the people.

At least 80 people were killed across the country on Sunday alone, according to the opposition Syrian Observatory for Human Rights. A total of around 15,000 people have been killed since the uprising began in March 2011.