Representatives of international aid and humanitarian organizations operating in war-wracked Yemen say they are increasingly being targeted by the Iran-backed Houthi rebels on a scale that could jeopardize efforts to assist millions of civilians caught in what is already the world’s worst humanitarian crisis.

Aid workers told Foreign Policy that they are facing threats of attack in the areas controlled by the Houthis, which includes western parts of the country and Yemen’s capital, Sanaa.

Members of the group detained one humanitarian worker, Awfa al-Naami, in late January and held her for weeks, releasing her on Feb. 16 after sustained diplomatic pressure. Naami is the country manager for Saferworld, a U.K.-based nonprofit operating in Yemen. Her detention rattled other aid officials and stoked fears that the group would stage similar abductions. (Saferworld declined to comment for this story.)

The Houthis are likely testing the international community to see how much harassment and intimidation they can get away with, according to two aid workers. The two spoke to FP on condition of anonymity, fearing for their own safety and that of their colleagues.

“They’re continuing to push the boundaries,” one of them said.

If aid groups continue to be targeted and threatened, they could be forced to scale back or even shutter humanitarian and peace-building operations, which include delivering food and medical supplies and conducting programming on education and women’s participation in civil society. Any decrease in assistance could exacerbate the country’s humanitarian crisis.

Aid is “one of the things keeping millions alive right now,” said Scott Paul, who works on Yemen issues for Oxfam America, which operates in the country. “If things continue to go on as they are, principled assistance could be endangered. That puts millions at risk.”

Rasha Mohamed, a Yemen researcher at Amnesty International, said humanitarian workers should have “unhindered and unimpeded access” to civilians in war zones.

The conflict in Yemen, now in its fourth year, has pitted the Houthi rebels against the Yemeni government backed by Saudi Arabia, the United Arab Emirates, and other Sunni Muslim-majority countries. Tens of thousands of people have died in the war, many in bombing campaigns by the Saudi coalition, which is supported by the U.S. military. Millions of Yemenis have been pushed to the brink of famine.

In Washington, the conflict has sparked a fierce showdown between President Donald Trump’s administration and Congress—including many prominent Republican lawmakers—over whether the United States should withdraw its support from the Saudi-led coalition.

The United States provides weapons sales to some countries in the coalition, as well as intelligence and surveillance support. Late last year, the United States halted air-to-air refueling support for the Saudi bombing campaign following mounting pressure from Congress.

AFP.