WASHINGTON (Reuters) - Two U.S. senators urged Secretary of State Mike Pompeo on Tuesday to withdraw the nomination of Ronald Mortensen, who has been criticized for harsh remarks about undocumented immigrants, to a top department position dealing with refugees.

Republican Senator John McCain and Democrat Chris Coons said Pompeo should pick someone else to be assistant secretary of State for population, refugees and migration. The letter was sent as the Trump administration faces criticism in the United States and abroad over its policy of separating parents and children immigrants on the border with Mexico.

“At a time when more than 65 million people are displaced worldwide, the nomination of Mr. Mortensen for this position sends a chilling message to all those around the world who look to the United States as a beacon of hope and security for persecuted peoples,” the two lawmakers said in a letter.

At least one other Republican senator also opposes Mortensen. Senator Jeff Flake tweeted last month that he would not support the nominee. Senator Bob Menendez, the top Democrat on the Foreign Relations Committee, has also raised concerns about Mortensen.

Flake and Coons are also members of the foreign relations panel, which would conduct Mortensen’s confirmation hearing. McCain is one of the Republican party’s most respected foreign policy voices and chairman of the Senate Armed Services Committee.

President Donald Trump nominated Mortensen for the position on May 24. A retired foreign-service officer, he has written dozen of opinion columns against illegal immigration. And he is a fellow at the Center for Immigration Studies, which advocates for reduced immigration to the United States and has been called a hate group by the South Poverty Law Center.

State Department spokeswoman Heather Nauert told reporters at a briefing on Tuesday that she had not seen the letter and could not comment.