Ban Ki-moon says "much work now lies ahead" to implement the agreement
The United Nations Secretary-General Ban Ki-moon has welcomed a ceasefire agreement for Syria - and is calling on all sides to abide by it.
The United States and Russia have announced the deal will come into effect on Saturday.
But the plan allows continuing attacks, including air strikes, against Islamic State, the Nusra Front and other groups classed as terrorists by the UN.
The statement from Mr Ban adds that, "much work now lies ahead to ensure its implementation, and the international community, the ISSG and the Syrian parties must remain steadfast in their resolve".
The UN head has also condemned the bombings in the Syrian cities of Damascus and Homs yesterday, which are reported to have resulted in the deaths of at least 155 civilians. Islamic State has claimed responsibility for the attacks.
More than a quarter of a million people have died since violence broke out in Syria in 2011.
Speaking in Jordan yesterday, US secretary of state John Kerry said, "the answer to the Syrian civil war will not be found in any military alliance with [Syrian president] Assad, let me make that clear.
"I am convinced it can be found in a broadly-supported diplomatic initiative aimed at a negotiated political settlement with a transitional governing council... in which we unite all Syrians who reject dictatorship and terrorism, and want to build a new future for Syria," he added.