Arizona Sen. John McCain on Monday called the report that President Donald Trump shared classified intelligence with Russian officials “deeply disturbing.”

A Washington Post report, which cited current and former U.S. officials, found that Trump revealed highly classified intelligence about ISIS threats with Russian officials during a meeting in the Oval Office last week.

“If true, deeply disturbing…” McCain, a Republican, said in a tweet, linking to the Washington Post story.

“We certainly don’t want any president to leak classified information, but the president does have the right to do that,” McCain said earlier Monday evening, according to the Associated Press.

Republican House Speaker Paul Ryan called for an explanation from the White House.

“We have no way to know what was said, but protecting our nation’s secrets is paramount,” a spokesperson for Ryan said in a statement. “The speaker hopes for a fully explanation of the facts form the administration.”

Tennessee Sen. Bob Corker, a Republican, criticized the White House in comments to reporters on Monday.

“They are in a downward spiral right now and have got to figure out a way to come to grips with all that’s happening,” Corker said, according to CNN.

Trump Administration officials denied the Post report.

“At no time — at no time — were intelligence sources or methods discussed. And the president did not disclose any military operations that were not already publicly known,” National Security Adviser H.R. McMaster said Monday night.

“I was in the room. It didn’t happen,” he added.

Get our Politics Newsletter. The headlines out of Washington never seem to slow. Subscribe to The D.C. Brief to make sense of what matters most. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Write to Katie Reilly at Katie.Reilly@time.com.