US President Barack Obama walks with Britain's Prime Minister David Cameron during the G8 summit at the Lough Erne golf resort
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Live: Latest BBC coverage of Syria conflict

The UK is to put a resolution to the UN Security Council later on Wednesday "authorising necessary measures to protect civilians" in Syria.

The resolution will be put forward at a meeting of the five permanent members of the council, UK Prime Minister David Cameron said on Twitter.

Earlier a team of UN weapons inspectors resumed work probing an suspected chemical weapons attack on 21 August.