Trump’s trip to the United Arab Emirates come as Senate Democrats push that wealthy Gulf country to stop what the U.S., U.N. and international rights groups say are arms shipments to one of the sides in Sudan’s devastating war.

The U.S. has sanctions on UAE companies over weapons deliveries to Sudan’s Rapid Support Forces, whose fight with a rival has uprooted millions of Sudanese and spurred atrocities and starvation. Aid groups call it one of the world’s worst humanitarian disasters.

UAE’s arms deliveries also are raising the risk of a “broader conflict that could destabilize the whole region,” Sen. Jeanne Shaheen, the ranking Democrat on the Senate Foreign Relations Committee, said this week.

Ahead of Trump’s trip, “my message to the UAE is to stop extending the aid” and work to stop the fighting, Shaheen said.

The UAE, a federation of seven sheikhdoms on the Arabian Peninsula and a U.S. ally, has been repeatedly accused of arming the RSF, something it has strenuously denied despite evidence to the contrary.