McCain, the 2008 Republican presidential nominee, said in an appearance on ABC's "This Week" program the president does not have a plan to deal with the suspected terrorists housed at the controversial prison.
"What should have taken place, in my view, was the announcement of the closing and an announcement of exactly how we are going to put these people on trial," McCain said. "That is a terrible mistake."
McCain reiterated his support for closing Guantanamo Bay, but said Obama is doing so without a clear plan.
"I'm for closing Guantanamo," McCain said. "And I said I was for closing it. But I'm for a comprehensive solution of all the issues surrounding Guantanamo, which now obviously are facing serious roadblocks in Congress because the announcement was made without addressing serious underlying problems."
Notable deaths of 2014 [PHOTOS]