The Obama administration announced the release of another Guantánamo Bay detainee on Saturday, rebuking recent calls from congressional Republicans to stop the transfers entirely.

A Saudi man who has spent 12 years at the wartime detention facility, Muhammed Murdi Issa al-Zahrani, will return to Saudi Arabia and enter the kingdom’s rehabilitation program. The transfer brings the detainee population of a prison Barack Obama has vowed for six years to close down to 142 men, 72 of whom the Pentagon considers pose little enough threat as to be eligible for transfer.

Zahrani is the seventh man the administration has transferred out of Guantánamo in two weeks, and the 13th in 2014. His transfer follows Thursday’s announcement that Slovakia will take two detainees and Georgia will resettle three more. Another detainee was transferred to Kuwait the day after Obama’s Democratic party lost control of the Senate and deepened its minority in the House of Representatives.

The latest transfer comes despite intensifying calls from congressional Republicans, empowered after the midterm elections rout, decrying the transfers as unacceptable and irresponsible.

“What the Obama administration is doing is dangerous and, frankly, reckless,” the retiring chairman of the House armed services committee, Buck McKeon, said after Thursday’s transfers.

“They have chosen many times to put politics above national security. It’s time they stop playing with fire and start doing what’s right. Until we can assure the terrorists stay off the battlefield, they must stay behind bars.”

McKeon joined with the New Hampshire senator Kelly Ayotte last month in writing to the administration urging an end to the transfers, after a report from Fox News alleged that ex-Guantánamo fighters were fighting in Iraq and Syria. Asked about the report during a recent committee hearing, defense secretary Chuck Hagel generically stated that some former Guantánamo detainees have “gone back to the fight, to the battlefield”, but stopped short of saying former detainees are fighting on behalf of the Islamic State (Isis).

Opposition to the transfers continues the political acrimony over Obama’s May decision to trade five Taliban detainees for captured army sergeant Bowe Bergdahl. Although George W Bush released hundreds of Guantánamo detainees during his presidency without significant political encumbrance, and the Republican 2008 presidential candidate John McCain favored closing the facility, Republicans decided early in Obama’s presidency to thwart his campaign pledge to close Guantánamo. They have thus far succeeded.

For Obama’s part, the continued piecemeal transfers are consistent with the tone of defiance to the Republicans he has sounded since their congressional victory. His new immigration plan, announced on Thursday, sparked widespread Republican opposition for its unilateralism as well as its substance.

Yet Obama’s decision not to shutter the detention facility wholesale or charge with war crimes the vast majority of detainees he seeks to retain falls short of the outcome desired by human rights campaigners. Earlier this month, a federal judge handed Obama a victory by declining to intervene in the force feedings Guantánamo officials administer to detainees on hunger strike. The Justice Department has until 2 December to announce if it will appeal the judge’s order to disclose videotapes of some of the feedings.

Obama “should take advantage of this momentum and waste no time in transferring the remaining men who he does not intend to charge criminally”, the Center for Constitutional Rights said in a statement issued after the announcement of Zahrani’s transfer.

Paul Lewis, the administration’s special envoy for Guantánamo transfers, hailed the recent spate of transfers in a statement.

“This strikes a responsible balance and reflects the careful deliberation the secretary of defense brings to the transfer process, and follows a rigorous process in the interagency to review several items including security review prior to any transfer.”