Donald Trump also repeated his previously declared view that accusations made by Turkey that the Protestant church leader has no links to espionage and terrorism are false.
Speaking to MSNBC from the White House, he said: "You know, we have pastor Brunson, a wonderful Christian pastor and he's right now in Turkey.
"He's been there a long time and they say he's a spy but he's not a spy. We're all going to work - and we've been working - for his release."
Mr Trump addressed reporters during a meeting with the US Mormon missionary Joshua Holt who was unexpectedly released by Venezuela at the weekend, having spent two years in jail over claims he was spying for the CIA.
First detained in October 2016, Andrew Brunson (pictured below with his wife, Norine) was accused by Turkish officials of harbouring links with Fethullah Gülen, a Turkish preacher they blame for a failed coup in the country in July 2016.
Supporters claim there is "no evidence" to support claims made against Mr Brunson. They have described him as a political prisoner being held as a bargaining chip by Turkey as it seeks the extradition of Mr Gülen from the US.
Referring to Mr Brunson, the Donald Trump continued: "He's having a hard time, there's a trial going on but the trial is not so much of a trial.
"We're talking to the folks in Turkey about doing something about it but Pastor Brunson, I hope you can us, we'll be helping you at some point."
"We've been working on it for a while. It's been a long time and he's a totally innocent man."
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