he speaks about them is appalling, as if welfare or terrorism were the only purposes they could have in coming to our country."

"His reaction to unflattering news stories, calling them 'fake news,' whether they're credible or not, is copied by autocrats who want to discredit and control a free press," McCain writes. "He has declined to distinguish the actions of our government from the crimes of despotic ones. He has showered with praise some of the world's worst tyrants."

Vice President Mike Pence talks about Sen. John McCain in Tempe Vice President Mike Pence talks about Sen. John McCain at an "America First Policies" event in Tempe on May 1, 2018.

Pence praises McCain

Earlier this week, Pence praised McCain, the 2008 GOP presidential nominee, at a stop in Tempe.

"You know,he's spent an entire lifetime fighting for the country that he loves, in the United States Navy, in the House of Representatives and representing Arizona in the United States Senate," Pence said. "Now I know he's fighting this illness with courage and with strength."

RELATED: Pence: People across U.S. are praying for McCain

McCain, 81, since July has been battling a deadly form of brain cancer called glioblastoma. He has not been in Washington, D.C., since December. Official updates on his health have been rare, but he is currently at his family retreat in Cornville, near Sedona.

In an interview with CBS' "60 Minutes" last year, McCain said he wanted a memorial service held at the U.S. Naval Academy, his alma mater. In his forthcoming memoir, "The Restless Wave," McCain indicates