WASHINGTON — The Pentagon has rejected a military request that it spend $195.7 million to renovate the prison at Guantánamo Bay, Cuba, an official with the United States Southern Command said on Tuesday. The Obama administration has been trying to close the prison, but Congress has prevented it from doing so.

Citing facilities that were built to be temporary a decade ago and are deteriorating, Gen. John F. Kelly, the head of the Southern Command who oversees Guantánamo, requested money in March to rebuild structures associated with the complex. The request included $49 million to replace a semi-secret prison where a small number of “high-value” detainees like Khalid Shaikh Mohammed, the self-described architect of the Sept. 11 terrorist attacks, are housed.

While the money was denied sometime during the summer, it was publicly disclosed on Tuesday by a Southcom spokesman, Col. Greg Julian of the Army, in response to a question from The New York Times. He said the request had been rejected “because of a lack of Congressional support to use the overseas contingency funding that we sought to complete those projects. So now we are working on various measures to mitigate some of the conditions of the facilities.”

Southcom’s request was to use funds that Congress had already appropriated for “overseas contingency” matters. But after a review by the secretary of defense and the White House’s Office of Management and Budget, the Obama administration decided not to approve the spending, he said.