As UN military observers left Syria today at the end of a failed mission, increased fighting broke out in Damascus and southern Syria, killing at least 120 people, Reuters reported.
Two activist groups, The Syrian Observatory for Human Rights and the Local Coordination Committees, reported airstrikes and heavy shelling in residential areas.
On Sunday, Lakhdar Brahimi, who replaced Kofi Annan as the UN-Arab League envoy to Syria, said he did not know how to resolve the conflict without the support of a unified UN Security Council.
"If they spoke in one voice and were clearly supportive of what I will be doing on their behalf, that is what I need," Brahimi said. "Without a unified voice from the Security Council, I think it will be difficult."
On Monday, Brahimi told the BBC he was not ready to call for Assad's removal.
"I am not in a position to say yet, because I was appointed a couple of days ago. I am going to New York for the first time to see the people who I am going to work for, and I am going to Cairo see the Arab League," he said.
Meanwhile, President Obama said today that Assad would face "enormous consequences if we start seeing movement on the chemical weapons front or the use of chemical weapons." He called the use of biological agents "a red line" that would "change my calculus" of involvement in Syria.
Syria publically admitted in July that it maintains a large stockpile of chemical weapons.