Trump made the announcement in a social media post hours after he accused former president Barack Obama of disclosing classified information when Obama recently suggested in a podcast interview that aliens were real.
"I don't know if they're real or not," Trump told reporters on Air Force One, and said of Obama, "I may get him out of trouble by declassifying".
In a post on his social media platform on Thursday night, US time, Trump said he was directing government agencies to release files related "to alien and extraterrestrial life, unidentified aerial phenomena (UAP), and unidentified flying objects (UFOs), and any and all other information connected to these highly complex, but extremely interesting and important, matters".
Obama, who made his comments in a podcast appearance over the weekend, later clarified he had not seen evidence that aliens "have made contact with us", but said, "statistically, the universe is so vast that the odds are good there's life out there".
Trump told reporters on Thursday that when it came to the prospect of extraterrestrial visitors: "I don't have an opinion on it. I never talk about it. A lot of people do. A lot of people believe it."
Trump's daughter-in-law Lara Trump suggested this week he was ready to speak about it, however, when she said on a podcast the president had a speech prepared to deliver on aliens that he would give at the "right time".
White House press secretary Karoline Leavitt responded with a laugh when she was asked about it.
"A speech on aliens would be news to me," she told reporters on Wednesday.
Public interest in unidentified flying objects and the possibility of the government hiding secrets of extraterrestrial life re-emerged after a group of former Pentagon and government officials leaked US Navy videos of unknown objects to The New York Times and Politico in 2017.Â
The renewed scrutiny prompted Congress to hold the first hearings on UFOs in 50 years in May 2022, though officials said the objects, which appeared to be green triangles floating above a navy ship, were likely drones.
Since then the Pentagon has promised more transparency on the topic. In July 2022 it created the All-Domain Anomaly Resolution Office, or AARO, which was intended to be a central place to collect reports of all military UFO encounters, taking over from a department task force.
The information that has been made public shows the vast majority of UFO reports made by the military go unsolved but the ones that are identified are largely benign in nature.
An 18-page unclassified report submitted to Congress in June 2024 said service members had made 485 reports of unidentified phenomena in the past year but 118 cases were found to be "prosaic objects such as various types of balloons, birds, and unmanned aerial systems".
"It is important to underscore that, to date, AARO has discovered no evidence of extraterrestrial beings, activity, or technology," the report stressed.
