WASHINGTON - US President Donald Trump said on Wednesday the United States is holding negotiations to try to win the release of US hostages held abroad, but he declined to say in what countries.

Trump made the remark at a White House event welcoming Danny Burch, an oil engineer who Trump said last month was reunited with his family after 18 months in captivity in Yemen.

"We have a few negotiations going on right now. I won't tell you where, because we don't want to blow the negotiation out the window," Trump told reporters.

"I love doing it, because I love the end result. This is the end result: a happy man with a happy family."

The Trump administration has secured the release of a number of US citizens held by other countries for apparent political reasons. Trump himself put the number at 20 during his meeting in the Oval Office with Burch, who thanked the president and senior officials involved in the negotiations.

A number of US citizens are now held in Iran, Saudi Arabia and Turkey. Most of those freed so far have been from the Democratic People's Republic of Korea.

Pyongyang released three Americans ahead of Trump's Singapore summit with DPRK top leader Kim Jong-un last year and freed another detainee later in the year. It obtained the release of American pastor Andrew Brunson from Turkey in October.

Reuters