The United States has stepped up pressure on Syria, calling it a barrier to democratic change in the Middle East.
The US Secretary of State, Condoleezza Rice, said it was becoming clear that Syria was obstructing efforts for reform in Lebanon, Iraq and the Palestinian territories.
Speaking in London, Dr Rice also said there was firm evidence that the militant Islamic Jihad group's headquarters in Syria was involved in last Friday's suicide bomb attack in Tel Aviv.
Meanwhile, Syria's President Bashar al-Assad has indicated that its 14,000 troops might be withdrawn from Lebanon within months.
The announcement comes as demonstrators in Beirut continue to call for the withdrawal of troops.
