The US Defense Department is sending a team to military sites in two different states to investigate the possibility of relocating some inmates from the US military prison in Guantanamo Bay, Cuba, to American soil.

The Pentagon notified the US Congress on Friday that the team was already visiting the military prison at Fort Leavenworth, Kansas, and would then survey the military prison at Charleston, South Carolina, in the coming weeks, US media reported on Saturday.

The White House said last month that the Obama administration is in the final stages of drafting a plan and sending it to Congress to close Guantanamo Bay.

The transfer of inmates to the US requires approval from Congress, since lawmakers would have to change a 2010 law that bans transfers of Guantanamo detainees to US soil for any reason.

The closure of Guantanamo is strongly opposed by Republicans in Congress, who say any transfer or release of prisoners could lead to more terrorist attacks.

Washington has slowly been sending Guantanamo prisoners back to their native countries or to third nations, and may have to transfer some to the US if the facility is to close.

The closure of the detention facility was among the main election promises of Obama during the 2008 presidential election. Obama vowed to close it within a year when he came to office in 2009.

The US military prison was set up by the Pentagon after the September 11, 2001, attacks to hold suspected al-Qaeda and Taliban detainees. Many of the inmates there have gone on hunger strike to protest their conditions at the prison.

Last year, Amnesty International said the continued operation of Guantanamo by the US and the torture of detainees there was a prime example of America’s double standard on human rights.