WASHINGTON, June 30-- The Obama administration on Tuesday appointed a new special envoy to lead U.S. President Barack Obama's long-standing promise to close the internationally denounced detention center at Guantanamo Bay in Cuba.

U.S. Secretary of State John Kerry said on Tuesday that the appointment of Lee Wolosky, a former National Security Council director under former President Bill Clinton and President George W. Bush, as the U.S. State Department's Special Envoy for Guantanamo Closure was aimed at phasing out the Guantanamo detention camp in a "timely manner".

The appointment of Wolosky came six months after the previous envoy Cliff Sloan resigned last December amid friction between the State Department and the Pentagon over delays in prisoner releases. The position of the special envoy had been vacant for six months.

Though pledging to shutter the controversial Guantanamo detention camp shortly after he took office in 2009, Obama's effort to close the detention camp, infamous for torturing prisoners and holding prisoners without charge or trial, failed to yield results.

As Obama's presidency is winding down, the prospect for the closure of the detention camp looked dim, as the U.S. Congress refused to budge from its stance of barring the Pentagon from transferring some prisoners to the United States.

Speaking to the U.S. TV network CBS News last week, U.S. defense chief Ash Carter acknowledged that he was not confident that the prison could be closed before Obama's presidency came to an end.

Carter also stressed that any closure plan must include moving some prisoners whom the Pentagon deemed too dangerous to be released to a facility inside the United States.

Currently, there are 116 prisoners left at the Guantanamo detention camp, including 52 who are approved for transfer.

The majority of the prisoners eligible for transfer come from Yemen, but as violence and terrorist attacks continued to convulse Yemen, the Obama administration would have to locate other countries which would be willing to accommodate those prisoners.