Syria ceasefire comes into effect under Annan plan
A ceasefire for Syria proposed by UN-Arab League envoy Kofi Annan has come into force, but Western countries have publicly doubted Syria's willingness to stick to it.
Syria has said it would abide by the ceasefire but reserved the right to respond to attacks.
The BBC's Jim Muir, in Beirut, says there are many issues to be overcome, any of which could derail the peace process.