Senate Minority Leader Mitch McConnell (R-Ky.) on Thursday ridiculed President Barack Obama’s strategy for closing the Guantánamo Bay, Cuba, prison, arguing Obama’s “flowery campaign speech— and desire for global acceptance are not a substitute for a concrete plan.

“With all due respect to the president, what we need here is not a speech but a plan,— McConnell said, arguing that Obama was involved in “a quest for popularity in Europe.—

In a speech Thursday, Obama sought to push back against criticism of his Guantánamo plan. He tried to assure the public that no detainees would be let loose on American soil.

But McConnell, who has spearheaded the GOP’s three-month campaign to force Democrats’ hand on the issue, rejected Obama’s arguments, maintaining that the administration has no concrete plan for closing the base.

“A big, flowery campaign speech is fine. But what the Congress voted for yesterday was not a speech but a plan,— McConnell said in reference to the Senate’s overwhelming vote Wednesday to withhold funding from the administration to close the prison until a plan is developed.

McConnell’s criticism is perhaps his harshest yet against the administration, and was a clear signal of the GOP’s confidence in the ongoing fight over Guantánamo’s closure.