Syria crisis: 'We must put an end to atrocities' - Ban Ki-moon
3 September 2013 Last updated at 19:27 BST
The UN Secretary General Ban Ki-moon has said that if it is proved chemical weapons were used in Syria, the UN Security Council must unite and take action.
He said the organisation's charter permitted military action only in self-defence or with the agreement of the Security Council.
But he added that military action in response could unleash more turmoil.