By Mark Hosenball

WASHINGTON (Reuters) - In the first six months of 2016, two more militants released from the U.S. naval base at Guantanamo Bay, Cuba, have returned to fighting, the U.S. government said on Wednesday.

Washington has confirmed that a total of nine people freed from Guantanamo have rejoined militant groups since President Barack Obama took office in 2009, according to a report issued on Tuesday by the Office of Director of National Intelligence, or ODNI.

The report said the number of militants freed by the Obama administration whom U.S. agencies "suspect" of having returned to action dropped to 11 from 12 between January and July.

An official familiar with the latest statistics said this number dropped because a freed detainee previously categorized as "suspected" of returning to the battlefield now has been confirmed to have done so.

The United States opened the Guantanamo detention facility in 2002, the year after the Sept. 11 attacks by Islamist militants on New York and Washington, to hold what it described as foreign terrorism suspects. Most have been held without charge or trial for more than a decade, drawing international condemnation.

Obama had hoped to close the prison during his first year in office. In February, he rolled out a plan aimed at shutting it, but that is opposed by many Republican lawmakers and some of his fellow Democrats.

Overall, the figures released by ODNI still showed that the administration of Obama's predecessor, Republican George W. Bush, released far more detainees from Guantanamo than the Obama administration has.

The figures show that 113 of the 532 detainees released by Bush - 21.2 percent - have returned to fighting, while the nine detainees released since 2009 who have re-engaged are only 5.6 percent of the prisoners freed by Obama.

In all, the Obama administration has released 161 prisoners from Guantanamo since 2009, 17 of them in the first six months of this year, ODNI said.

(Reporting By Mark Hosenball; editing by Grant McCool)