United Nations Secretary General Ban Ki-moon says the onus is on the Syrian government to keep to its promise to observe a ceasefire that took effect yesterday.

Ban Ki-Moon says the situation in Syria looks calmer and he is now working with the UN Security Council to send an observer team as soon as possible.

However, the main opposition in Syria says the ceasefire is only being partially observed as heavy weapons and government troops remain deployed in several cities.

The Syrian National Council says security forces are continuing to attack civilians.