The men — four Syrians, a Palestinian and a Tunisian — are among the more than 70 detainees who have long been cleared for release from the U.S. detention facility because they are not deemed an ongoing threat. The move would mark a significant step in the Obama administration’s long-stymied quest to shut down Guantanamo Bay, where 149 inmates remain.

A congressional aide who spoke on the condition of anonymity said key lawmakers were notified about the imminent transfer last Thursday. None has publicly criticized the proposal. By law, the Pentagon must notify members of Congress of its intention to release Guantanamo Bay inmates at least 30 days in advance.

The men’s move to Uruguay would be the first release from the prison since the Obama administration incensed lawmakers in May by freeing five Afghan detainees in exchange for Army Sgt. Bowe Bergdahl, who had been held by the Taliban for five years, without notifying them.