At a congressional hearing on unidentified flying objects, lawmakers called for more transparency from the US government on the issue. "I think we're going to look at what we can do to make more of this information public," Republican Representative Glenn Grothman said at the conclusion of Wednesday's hearing.

Two former military pilots and a former intelligence official answered questions from a special committee of the US House of Representatives at the meeting and shared their sightings and analysis of unidentified flying objects. Many sightings are not reported at all because the pilots are afraid of losing their jobs, they complained.

The sightings are being taken seriously and are being investigated, National Security Council communications director John Kirby told reporters on Wednesday. "We don't have the answers for what these phenomena are."

In January, for the first time in decades, Congress held a hearing on this topic, after the Pentagon had presented reports in recent years that there were no explanations for dozens of celestial phenomena from the past two decades - but also no evidence of secret ones Technology from other countries or extraterrestrial life.

In June, a group of experts from the US space agency Nasa held a first public meeting and advocated more and better data on observations of unidentified flying objects. Many of these observations from the past could not be clarified because the data were too small and of poor quality, it said. The Pentagon had also criticized insufficient data.