The Pentagon says another prisoner has been released from the detention center on the U.S. military base in Guantanamo Bay, Cuba.

A Pentagon statement Thursday said Ahmed Abdel Aziz, 45, has been sent back to his native Mauritania after 13 years in custody at Guantanamo.

He is the 14th prisoner released this year amid a continuing standoff between President Barack Obama and Congress over Obama’s attempt to close the detention center.

"The United States is grateful to the Government of Mauritania for its
willingness to support ongoing U.S. efforts to close the Guantanamo Bay
detention facility," the Pentagon said. "The United States coordinated with the Government of Mauritania to ensure this transfer took place consistent with appropriate security and humane treatment measures."

Aziz was initially detained as a suspected member of al-Qaida with ties to some of the most senior members of the terrorist organization. He was captured by Pakistani authorities at a suspected al-Qaida safe house and turned over to the U.S. He was never charged with a crime.

There are now 113 prisoners at Guantanamo.

VOA's Pentagon correspondent Carla Babb contributed to this report.  Some material came from AP