The US has called for a swift cessation of hostilities in Yemen, where three years of civil war have caused the world's worst humanitarian crisis.

Defence Secretary James Mattis said all parties needed to take part in UN-led peace talks within the next 30 days.

Secretary of State Mike Pompeo meanwhile urged the Saudi-led coalition battling the rebel Houthi movement to end its air strikes on populated areas.

The US has faced growing pressure to end its support for the coalition.

Why is there a war in Yemen?

Yemen has been devastated by a conflict that escalated in early 2015, when the Houthis seized control of much of the west of the country and forced President Abdrabbuh Mansour Hadi to flee abroad.

Alarmed by the rise of a group they saw as an Iranian proxy, the UAE, Saudi Arabia and seven other Arab states intervened in an attempt to restore the government. They have received logistical and intelligence support from the US, UK and France.

At least 6,660 civilians have been killed and 10,560 injured in the fighting, according to the United Nations. Thousands more civilians have died from preventable causes, including malnutrition, disease and poor health.

What did the US officials say?

Speaking at the US Institute of Peace in Washington on Tuesday, Mr Mattis said the US had been watching the conflict "for long enough".

"We have got to move towards a peace effort here, and we can't say we are going to do it sometime in the future. We need to be doing this in the next 30 days," he said.

Mr Mattis added that all sides were being urged to meet UN special envoy Martin Griffiths in Sweden in November and "come to a solution". BBC