Under pressure to demonstrate a renewed commitment to shutter the prison at Guantanamo Bay, Cuba, President Obama has tapped a high-powered Washington attorney as one of two special envoys dedicated to brokering a deal to close the facility.

Obama chose Clifford Sloan, an attorney with extensive experience in all three branches of government, to reopen the State Department’s Office of Guantanamo Closure, which has been in limbo and effectively shuttered since the administration gave up attempts to close the prison in the face of ardent opposition in Congress, according to an Associated Press report. A formal announcement is expected Monday.

Sloan, a partner at Skadden Arps, Slate, Meagher and Flom LLP law firm, has served in Democratic and Republican administrations. Most recently, he was an informal adviser to Secretary of State John Kerry, who recommended him for the post.

“I appreciate his willingness to take on this challenge,” Kerry told the AP. “Cliff and I share the president’s conviction that Guantanamo’s continued operation isn’t in our security interests.”

The president promised to name two special envoys — one at the State Department and another at the Pentagon — to restart negotiations on closing Guantanamo Bay during a major foreign policy speech at the National Defense University in May.

In that speech, Obama also lifted a ban on sending the detainees to Yemen that the administration had imposed after the botched bombing of a commercial flight bound for Detroit on Christmas Day 2009. U.S. intelligence officials believe the underwear bomb used in the attempted attack was built by an Al Qaeda affiliate in Yemen. The majority of the 166 remaining prisoners are Yemeni.

Before the Sloan choice, Obama was getting an earful last week from human rights advocates, frustrated that they had seen no concrete signs of progress nearly four weeks after the speech.

“The president has a window of opportunity to build on the growing bipartisan support for closing Guantanamo,” Human Rights First President Elisa Massimino said last week. “It should begin by immediately initiating transfers of as many of the 86 detainees as possible, including those from Yemen, who already have been cleared for transfer.”

David Remes, an attorney who represents several Guantanamo Bay detainees, said he was encouraged by a trip White House Chief of Staff Denis McDonough and sens. John McCain, R-Ariz., and Dianne Feinstein, D-Calif., made to Guantanamo Bay June 7 but was baffled by Obama’s decision to wait weeks before even appointing the envoys.

“The question is — is he really going to push for detainees transfers?” Remes said in an interview Friday with the Washington Examiner. “He promised once again, but he’s promised many times before. … He hasn’t transferred a single detainee since his speech — even though he has the power to do so.”

Advocates of closing the facility say Obama has the power as commander-in-chief to take unilateral action and shutter the facility, but the president has so far resisted doing so. Instead, he has blamed Congress for passing language in defense authorization bills preventing him from closing Guantanamo Bay.

On Friday the House passed a $638 billion defense bill that specifically prevents Obama from shuttering the facility, a measure the White House threatened to veto.

This article is based in part on wire service reports.