The Pentagon is preparing to release more prisoners from the Guantanamo Bay detention centre in Cuba, in the coming weeks, official sources in the US have revealed.

According to officials, there would be more transfers of detainees from Guantanamo Bay in December, but details on their numbers or nationalities were not provided, The Wall Street Journal reported Thursday.

The Pentagon last week transferred five detainees from the prison, sending two to Slovakia and three to Georgia.

“There does seem to be a renewed effort to make the transfers happen,” said Laura Pitter, the senior national security counsel for Human Rights Watch, which favours closing down the prison.

President Barack Obama had promised to close the Guantanamo Bay prison since he assumed office, but many Republicans have opposed those plans.

There are 143 detainees now at Guantanamo Bay, which at one time held nearly 800 terrorism suspects in the wake of the Sep 11, 2001 attacks.

At the time of its establishment in January 2002, the then US defense secretary Donald Rumsfeld had said that the prison camp was established to detain extraordinarily dangerous persons, to interrogate detainees in an optimal setting, and to prosecute them for war crimes.

By law, the US defense secretary must certify that any transfer of detainees out of Guantanamo would not pose a significant danger to US national security.

Senior officials at the White House are growing impatient as the clock ticks down on the Obama administration and the president’s promise of closing Guantanamo remains unfulfilled, officials said.