US Secretary of State Rex Tillerson met Tuesday with the foreign ministers of Britain, Saudi Arabia and the UAE to discuss "a political solution" to the conflict in Yemen, sources said.

The meeting was organised by top British diplomat Boris Johnson at the British embassy in Paris.

Tillerson and Johnson took part earlier Tuesday in the launch of an international initiative against chemical weapons, in particular in Syria.

"The conflicts in Syria and Yemen have created two of the worst humanitarian crises of our time," Johnson said ahead of the meetings.

"There can be no military solution to either conflict, only peaceful and carefully negotiated political solutions will truly end the suffering."

The UN has described Yemen, the poorest country in the Middle East, as the world's largest humanitarian disaster.

"We talked about the agreed critical goals in Yemen which are, first and foremost, to sustain the measures that have been taken over the course of the past weeks to expand" humanitarian access, a senior US State Department official said after the embassy meeting.

"That's what provides all of us the space" to pursue "further goals" of a political resolution to the conflict and a strategy to counter Iranian influence in Yemen, he added.

The conflict has left more than 9,200 dead and about 53,000 wounded.

A Saudi-led coalition has been waging an air campaign against Huthi rebels since March 2015 in an attempt to shore up the internationally recognised government of Abedrabbo Mansur Hadi.

Loyalist forces however have been struggling to reclaim territory lost to the rebels.

Riyadh, which has faced mounting criticism over its air raids which have killed numerous civilians and its blockade of the country, Monday announced $1.5 billion in humanitarian aid and an operation to facilitate relief.

Saudi and the US accuse Iran, Riyadh's regional rival, of smuggling weapons to the Huthi rebels.

"The Iranian proliferation has to come to an end. If it doesn't come to an end, there need to be consequences," the US official said, without specifying the form of retribution.