U.S. Sen. Jack Reed is calling on Rep. Devin Nunes, head of the House Intelligence Committee, to recuse himself from the investigation of Russia’s involvement in the 2016 U.S. presidential election.

Nunes’ ties with President Donald Trump’s administration were first put into question last week when he announced in a press conference that the Trump campaign has been subject to incidental government surveillance. Critics slammed Nunes for going to President Trump before briefing members of the intelligence committee.

Monday it was revealed that Nunes met with the source on White House grounds, which only raised questions of whether the source was from the White House.

Reed called the update “bizarre and inappropriate,” in a statement. Reed said assigning a special prosecutor would be the only way to ensure a full investigation.

“If they don’t, they will be compromising America’s ability to defend itself from future attacks,” said Reed.

Nunes told reporters Tuesday he would not step down from the investigation in Russian interference during the U.S. election.