As many as five detainees are expected to be moved from the detention facility in the next few days, with several more transfers anticipated in early 2015, the official said on condition of anonymity.
The news comes less than a week after the United States announced it had repatriated four detainees from Guantanamo to Afghanistan
, leaving 132 detainees at the U.S. naval base in southeastern Cuba.
President Barack Obama hinted at the intensified effort in an exclusive interview on CNN's "State of the Union" on Sunday, saying, "I'm going to be doing everything I can to close it."
"It is something that continues to inspire jihadists and extremists around the world, the fact that these folks are being held," Obama said. "It is contrary to our values and it is wildly expensive. We're spending millions for each individual there. And we have drawn down the population there significantly."
Once a detainee is deemed no longer a risk, they are either transferred back to their country of origin, or a third country that is willing to take them.
Sixty-four of the 132 remaining detainees have been ruled eligible for transfer.
Of the 64 eligible, 54 are from Yemen. But the United States is not willing, at this point, to send them back to Yemen because of concerns that the government -- under pressure from al Qaeda and Houthi militants -- cannot ensure they do not join al Qaeda elements there. The administration for the last several months has been trying to find a country that will take the Yemenis and provide security and human rights assurances for them.
The official said there are ongoing talks to try to find countries to take all 64 detainees approved for transfer.
An additional 20 detainees from Yemen still are considered too dangerous to be transferred, as are several detainees accused of involvement in the 9/11 attacks, including Khalid Sheikh Mohammed.
The number of remaining detainees is down significantly from the nearly 800 that had been held there after Guantanamo was repurposed to hold detainees from the United States' war on terror.
The administration of then-President George W. Bush claimed that, since Gitmo detainees weren't held on American soil, they could be considered "enemy combatants" and be denied some legal protections. Almost all of the 800 detainees were held without charges.
This legal limbo, as well as allegations of torture and other mistreatment, spurred criticism of the facility popularly known as Gitmo. Obama pledged to shut it down as part of his 2008 campaign, but saw his plans thwarted by opposition from Congress, which among other things prevented him from transferring remaining detainees to U.S. prisons.