Victoria Nuland, a spokeswoman for the State Department, said Washington was calling on its partners in the region to "tighten the noose" on Damascus in terms of political and diplomatic pressure.
Washington is said to be pushing for a U.N. Security Council resolution on Syria. Following a statement at the United Nations condemning Damascus for its crackdown on opposition groups, regional leaders have distanced themselves from Syrian President Bashar Assad.
"The Arab League (on Saturday) will be looking individually and collectively at what it can do to influence the situation in Syria, and we welcome that," said Nuland.
The United Nations estimates that more than 2,000 people were killed during the uprising against Assad since March.
Navi Pillay, the U.N. high commissioner for human rights, in statements Monday said more than 350 people were reportedly killed across Syria since the beginning of August.
Assad in statements published by the official Syrian Arab News Agency said Damascus "would never offer concessions to the west hence the Syrian people have chosen to have their will and independent sovereignty."