The trump campaign has acknowledged in a statement that president Obama was born in the US.
The statement follows an interview with the Washington Post newspaper in which Mr Trump had declined to say Mr Obama had been born in the US, saying instead that he did not want to answer the question.
Mr Trump had been a leader of the “birther” movement that questioned Hawaii-born Mr Obama’s citizenship as he was running for a second term as President.
The claim is a conspiracy theory that Mr Obama was actually born in Kenya and is therefore ineligible to be President.
In April 2011, Mr Trump had challenged Mr Obama to show his birth certificate, gaining approval from republicans including former Alaska Governor Sarah Palin.
Weeks later Mr Obama released his actual birth certificate from his native state of Hawaii.