President Barack Obama on Tuesday listed Americans held in Iran by name and said the United States will not give up until they are returned.

"We are not going to relent until we bring home our Americans who are unjustly detained in Iran," Obama said in a speech to the Veterans of Foreign Wars group.

"Journalist Jason Rezaian should be released. Pastor Saeed Abedini should be released. Amir Hekmati, a former sergeant in the US Marine Corps, should be released. Iran needs to help us find Robert Levinson," Obama said.