Yemen conflict: US boosts arms supplies for Saudi-led coalition

The US is also boosting intelligence sharing with the coalition, Deputy Secretary of State Antony Blinken said.

Aid agencies have warned of a looming humanitarian crisis in the Yemeni port of Aden, which has seen street battles between rebels and government allies.

Some 550 people are said to have died in the last fortnight of fighting.

According to the World Health Organization, nearly 2,000 people have been injured over the same period.

The UN children's agency, Unicef, says at least 74 of the dead are children, and more than 100,000 people have been displaced.

A spokeswoman for the International Committee of the Red Cross said the situation in Aden was "catastrophic to say the least".

"The war in Aden is on every street, in every corner," Marie Claire Feghali told the AFP news agency. "Many are unable to escape."

The Red Cross is one of several aid agencies trying to send more medical supplies and workers to Aden.

The port has been largely cut off since the Houthi rebels and their allies advanced upon it in March, forcing President Abdrabbuh Mansour Hadi to flee to Saudi Arabia.

Fighting escalated in the city this week, with reports of overflowing hospitals, hijacked ambulances and bodies left in the streets.