WASHINGTON • United States President Donald Trump called on Saudi Arabia to immediately end a blockade of Yemen that is preventing people in the war-torn country from receiving essential supplies, a rare criticism of a key US ally.

The Saudi-led military coalition fighting the Iran-aligned armed Houthi movement in Yemen's civil war started a blockade of ports a month ago after Saudi Arabia intercepted a missile fired towards its capital Riyadh from Yemen.

Although the blockade later eased and showed signs of breaking on Wednesday, Yemen's situation remained dire. About eight million people are on the brink of famine with outbreaks of cholera and diphtheria.

Mr Trump said in a statement on Wednesday that he has asked US officials "to call the leadership of the Kingdom of Saudi Arabia to request that they completely allow food, fuel, water, and medicine to reach the Yemeni people who desperately need it".

"This must be done for humanitarian reasons immediately," Mr Trump added.

The President's statement appeared to be a veiled criticism of Saudi Crown Prince Mohammed bin Salman, who has led the kingdom's campaign in Yemen and has been publicly praised by Mr Trump for his efforts to clamp down on terrorism and corruption.

Mr Trump issued the statement shortly after he announced the US was recognising Jerusalem as the capital of Israel, a move widely opposed in the Middle East.

The Norwegian Refugee Council (NRC) said the first food and fuel had arrived in Hodeidah and Saleef ports, but supplies were at a trickle compared to what was needed, since Yemen's population of 27 million was almost entirely reliant on imports for food, fuel and medicine.

A Saudi-led coalition in Yemen fighting Houthi rebels in a civil war has already produced what the United Nations calls the world's biggest humanitarian crisis.

The US is supporting the Saudi coalition with assistance including refuelling planes carrying out airstrikes and sharing intelligence. The US has also carried out drone strikes against terrorist camps in the country.

"President Trump's public call for Saudi Arabia to end the blockade is long overdue but hugely important," Mr Scott Paul, humanitarian policy lead at Oxfam America, said in a statement on Wednesday. "We should not overlook the fact that US support has helped create Yemen's horrific crisis."

At least 14,000 people have been killed or wounded since the Saudi-led offensive began in March 2015.

Nearly one million people have contracted cholera, and three million, out of a population of 28 million, are internally displaced, according to the UN. Yemen was already the poorest country in the Middle East.

BLOOMBERG, REUTERS