The US Office of the Director of National Intelligence reported 144 encounters with UFOs between 2004 and 2021.

However, the Pentagon’s effort to investigate anomalous, unidentified objects – whether they are in space, the skies, or underwater – has led to hundreds of new reports that are now being investigated, US defence officials said on Friday.

In June 2021 the Office of the Director of National Intelligence reported that between 2004 and 2021, there were 144 encounters with UFOs, 80 of which were captured on multiple sensors.

So far, “we have not seen anything, and we’re still very early on, that would lead us to believe that any of the objects that we have seen are of alien origin”, Ronald Moultrie, undersecretary of defence for intelligence and security, told reporters.

Sean Kirkpatrick, director of the Pentagon’s newly formed All-domain Anomaly Resolution Office (AARO) – which is investigating the sightings – did not rule out the possibility of extraterrestrial life and said he was taking a scientific approach to the research.

“I would just say that we are structuring our analysis to be very thorough and rigorous. We will go through it all,” Kirkpatrick said, speaking at the first news conference since AARO was established in July following more than a year of attention on UFOs that US military pilots had observed but were sometimes reluctant to report due to fear of stigma.

“We’ve had lots more reporting,” Kirkpatrick said.

When asked to quantify the number of new reports on potential UFO sightings, Kirkpatrick said “several hundred”.

Sightings of aircraft that do not appear to match known technology or that appear to defy the laws of physics have long been cited by amateur observers and sleuths as evidence of extraterrestrial life, with many speculating the US government has more evidence of UFOs than it has revealed.

An updated report from the Director of National Intelligence that will provide specific figures on new UFO reports received since 2021 is expected by the end of the year, officials said.

In May, the US Congress held its first hearing in more than half a century on the topic of UFOs, with multiple members expressing concern that whether the objects are alien or potentially new, unknown technology being flown by China, Russia or another potential adversary, the unknown creates a security risk.

Beyond unidentifiable objects, there is a lot of new technology – such as future stealth bombers and stealth fighters, drones and hypersonic missiles being fielded by both the US and China – that could be mistaken for a UFO.

Kirkpatrick said his office has been coordinating with the Pentagon and the US intelligence community to get the signatures of new US technology in order to rule out those aircraft or drones as possible UFOs.

He said that “very clear mechanisms” would be established with the Department of Defence and the US intelligence community to ensure that his office could identify and rule out US technology from potential UFO sightings.