US President Donald Trump has once again called on Turkish President Recep Tayyip Erdogan to release an American pastor being held on charges of espionage.

On Wednesday night, Trump tweeted: "A total disgrace that Turkey will not release a respected U.S. Pastor, Andrew Brunson, from prison. He has been held hostage far too long. Erdogan should do something to free this wonderful Christian husband & father. He has done nothing wrong, and his family needs him."