U.S. President Joe Biden is sending Senator Chris Coons to Ethiopia to meet with Prime Minister Abiy Ahmed and convey Biden’s “grave concerns” over the humanitarian crisis in the Tigray region, where thousands have died following fighting.

Washington also said it will provide nearly $52 million more in aid to address the humanitarian crisis in the region, but called for hostilities to end and human rights abusers to be held accountable.

Secretary of State Antony Blinken urged the immediate withdrawal of Eritrean forces, an end to the Ethiopian government’s deployment of regional forces in Tigray and increased humanitarian access.

“The humanitarian situation will continue to worsen without a political solution,” Blinken said in a statement.

Fighting between government troops and the Tigray People’s Liberation Front (TPLF) has killed thousands of people and forced hundreds of thousands from their homes in the mountainous region of about 5 million.

The United Nations has raised concerns about atrocities being committed in Tigray, while Blinken has described acts carried out in the region as ethnic cleansing. Ethiopia has rejected Blinken’s allegation.

“(The accusation) is a completely unfounded and spurious verdict against the Ethiopian government,” Ethiopia’s foreign ministry said on March 13, reacting to the allegation of ethnic cleansing.

“Nothing during or after the end of the main law enforcement operation in Tigray can be identified or defined by any standards as a targeted, intentional ethnic cleansing against anyone in the region,” it said. “The Ethiopian government vehemently opposes such accusations.”

Biden’s national security adviser Jake Sullivan said in a statement that Coons - a longtime Biden ally who represents the president’s home state of Delaware - would also consult with the African Union.

“Senator Coons will convey President Biden’s grave concerns about the humanitarian crisis and human rights abuses in the Tigray region and the risk of broader instability in the Horn of Africa,” Sullivan said. The senator serves on the Senate Foreign Relations Committee’s subcommittee on Africa and global health policy.

Officials in the prime minister’s office and at the foreign ministry did not immediately respond to requests for comment.

Coons said he looked forward to engaging with Abiy and conveying Biden’s concern.

“The United States is gravely concerned by the deteriorating situation in the Tigray, which threatens the peace and stability of the Horn of Africa region,” Coons said in a statement.

Ethiopia’s federal army ousted the TPLF from the Tigray capital Mekelle in November, after what it said was a surprise assault on its forces in the region bordering Eritrea.

The government has said most fighting has ceased but acknowledged there are still isolated incidents of shooting.

Ethiopia and Eritrea have denied the involvement of Eritrean troops in the fighting, although dozens of witnesses, diplomats and an Ethiopian general have reported their presence.