Joe Biden’s announcement is a pivot in US foreign policy, but experts say what exact support will be cut is unclear.
The United Nations’ humanitarian chief has said he is “very alarmed” by a Houthi rebel advance on the Yemeni government’s last northern stronghold.
Mark Lowcock, the UN undersecretary-general for humanitarian affairs, tweeted on Tuesday that an assault on Marib would endanger two million civilians and could cause hundreds of thousands to flee the city, which would have “unimaginable humanitarian consequences”.
The Houthis have this month resumed an offensive to seize Marib, some 120km (75 miles) east of Yemen’s rebel-held capital, Sanaa.
The city’s loss would be a major blow for Yemen’s internationally recognised government, which is backed by a Saudi-led military coalition.
“Now is the time to de-escalate, not to add even more to the misery of the Yemeni people,” Lowcock said in his tweet.
An assault on the city would put two million civilians at risk, with hundreds of thousands potentially forced to flee – with unimaginable humanitarian consequences. Now is the time to de-escalate, not to add even more to the misery of the Yemeni people.
— Mark Lowcock (@UNReliefChief) February 15, 2021
Military officials from the Yemeni government told AFP news agency that the rebels had advanced towards the city on two fronts overnight after heavy fighting with government forces.
Dozens from both sides have been killed in the past 24 hours alone, they said. The total casualty toll from the battle for Marib is unknown but reports indicate it is now in the hundreds.
“The rebels have advanced north and west of the city after seizing al-Zor [in Sirwah district] up to the western sides of Marib dam, and tightened their grip on hills overlooking supply lines for several fronts,” one of the officials said.
The Saudi-led coalition, which intervened militarily in Yemen six years ago, has been pounding rebel positions.
The Houthi-run Al Masirah television on Tuesday reported a total of 13 air raids in Marib – 11 on locations in the district of Sirwah, and two in the district of Madghal.
The fighting is endangering sprawling camps for internally displaced people, many of whom have fled several times before ending up in Marib, the only part of the north not under Houthi control.
Until early 2020, Marib had been spared the worst of Yemen’s long-running conflict, due to its strategic importance with its rich oil and gas reserves, and its location near the border of regional power Saudi Arabia.
It became a sanctuary for many in the early years of the war, taking in those hoping for a new start.
But that relative stability disappeared with fighting last year and – after a lull since October – residents once again risk being in the line of fire as the two sides battle for control.
“If fighting moves towards populated areas or these displacement sites, we will see people flee again and towards locations to the east and south of Marib city with even less resources,” International Organization for Migration spokeswoman Olivia Headon told AFP.
“Much of this is desert area so just think about what any displacement in that direction would mean for families’ access to water.”
Headon said approximately 650 families had been forced to flee in the recent surge of fighting and that another shift in the front lines would lead to further waves of displacement.
Yemen’s grinding conflict has killed tens of thousands and displaced millions, according to international organisations, sparking what the UN calls the world’s worst humanitarian crisis.
The surge in violence comes shortly after Washington decided to remove the rebels from its list of “terrorist” groups – a move that will come into effect on Tuesday – in order to ensure aid is unimpeded and to pave the way to restart peace talks.
The Biden administration also ended US support for Saudi offensive operations in a major policy shift from the previous Trump administration. The US president has since appointed an envoy for Yemen in his efforts to find a diplomatic solution to the conflict that has ravaged the poorest country in the Middle East.
Washington on Tuesday urged the rebels to halt their offensive, saying their advance on Marib threatened to undermine the Biden administration’s new drive to intensify diplomatic efforts to end the conflict.
“The Houthis’ assault on Marib is the action of a group not committed to peace or to ending the war afflicting the people of Yemen,” State Department spokesman Ned Price said in a statement.
“Marib is controlled by the legitimate government of Yemen,” he said. “This assault will only increase the number of internally displaced persons and exacerbate the humanitarian crisis in Yemen.”
Observers say the Houthis want to capture Marib as leverage before entering into any negotiations.
The rebels have also escalated attacks against Saudi Arabia in recent weeks.
Saudi state media said on Tuesday that another “booby-trapped drone” launched by the Houthis had been intercepted and destroyed near Abha airport, which earlier this month was struck by an attack that left an aircraft in flames.