The Pentagon on Thursday had four inmates transferred from the Guantanamo Bay prison to Saudi Arabia in a continuous bid to empty the facility as much as possible before U.S. President Barack Obama leaves office on Jan. 20.

His successor Donald Trump has publicly opposed the move.

Out of 55 people remaining in the prison, up to 19 are also eligible for transfer after receiving lengthy security reviews. Local media reported that they will be sent to at least four countries including Italy, Oman and the United Arab Emirates.

"The United States is grateful to the government of the Kingdom of Saudi Arabia for its humanitarian gesture and willingness to support ongoing U.S. efforts to close the Guantanamo Bay detention facility," the Pentagon said in a statement.

The latest transfer came just two days after Trump tweeted his opposition and called for stopping the action.

"There should be no further releases from Gitmo (the Guantanamo Bay prison). These are extremely dangerous people and should not be allowed back onto the battlefield," he wrote.

"He (Trump) 'll have an opportunity to implement the policy that he believes is most effective when he takes office on Jan. 20," White House Press Secretary Josh Earnest said in response.

Obama promised in his first presidential campaign eight years ago to close the facility. In his campaign toward White House, Trump pledged to keep it open.

The Republican-dominated Congress last year prohibited Obama from transferring any Guantanamo Bay prisoners to the mainland of the United States.

All the four inmates transferred Thursday are Yemenis. They had been held at the controversial detention facility for more than 14 years following the 9/11 terror attacks and the U.S.-launched Afghanistan War. Though suspected as terrorists related to al-Qaida, they had never been charged.

source: Xinhua