"I have directed officials in my administration 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", Trump said in a statement, without elaborating.
Saudi Arabia launched intensive military campaign against Yemen with the aim of eliminating the Houthi Ansarullah movement and reinstalling former President Abdrabbuh Mansour Hadi, who has close ties with the Saudis. Saudi Arabia severed diplomatic relations with Iran in January 2016 after Iranian demonstrators attacked Saudi diplomatic missions in response to the Saudi execution of a prominent Shiite dissident cleric.
He said he hoped a Saudi blockade of Yemen's ports, imposed after a Huthi missile was intercepted near Riyadh last month, would be lifted.
Speaking in Paris on Friday, Rex Tillerson, US secretary of state, urged Saudi Arabia to show restraint at the global levels.
Seven million people are believed to be on the brink of starvation and a cholera outbreak has caused more than 2,000 deaths.More news: Pro wrestler arrested after putting wife in headlock
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The Trump administration, like the Obama administration before it, has struggled to convince Saudi Arabia and the United Arab Emirates to pay more heed to the humanitarian crisis.
The ICRC has appealed for "bold measures" to provide life-saving care to civilians after the "unprecedented" escalation of fighting.
US President Donald Trump called for Saudi Arabia on Wednesday to immediately allow humanitarian aid to reach the Yemeni people, suggesting Washington had run out patience with a Saudi-led blockade that has been condemned by relief organizations.
"We're living in a state of fear".
Hariri recently returned to Beirut and said he would stay on as prime minister despite political tensions in that fractious nation.
Oxfam International applauded Trump's statement, calling it "long overdue but hugely important".