The death toll among the Syrian people has climbed to more than 7,500 in the nearly year-long uprising that began in March 2011.
In the last two months, an estimated 2,000 people have been killed.
The United Nations says Syrian government officials are responsible for "crimes against humanity."
Members of the U.N. Human Rights Council approved a resolution Thursday condemning Syria for "widespread and systematic violations" against civilians in its violent crackdown on opposition groups.
The resolution urged Syria to immediately stop all attacks on civilians and grant unhindered access to aid groups.
"Let's hope those who voted against the resolution today can see just how isolated they are in the international community," Britain's ambassador in Geneva, Peter Gooderham, said. "We very much hope this will have an impact in Beijing, in Moscow and of course in Damascus."
U.S. Secretary of State Hillary Clinton told members of Congress on Tuesday that President Assad is guilty of war crimes.
"Do you believe that Assad should be viewed by the international community as a war criminal?" Sen. Lindsey Graham, R-SC, asked Clinton.
"I think that based on definitions of war criminal and crimes against humanity, there would be an argument to be made that he would fit into that category," she replied.
Clinton also said Iran is helping to support the Assad regime.