A former Israeli space security chief has sent eyebrows shooting heavenward by saying that earthlings have been in contact with extraterrestrials from a “galactic federation.”

“The Unidentified Flying Objects have asked not to publish that they are here, humanity is not ready yet,” Haim Eshed, former head of Israel’s Defense Ministry’s space directorate, told Israel’s Yediot Aharonot newspaper. The interview in Hebrew ran on Friday, and gained traction after parts were published in English by the Jerusalem Post on Tuesday.

A respected professor and retired general, Eshed said the aliens were equally curious about humanity and were seeking to understand “the fabric of the universe.”

Eshed said cooperation agreements had been signed between species, including an “underground base in the depths of Mars” where there are American astronauts and alien representatives.

“There is an agreement between the U.S. government and the aliens. They signed a contract with us to do experiments here,” he said.

Eshed added that President Donald Trump was aware of the extraterrestrials’ existence and had been “on the verge of revealing” information but was asked not to in order to prevent “mass hysteria.”

“They have been waiting until today for humanity to develop and reach a stage where we will understand, in general, what space and spaceships are,” Eshed said, referring to the galactic federation.

The White House and Israeli officials did not immediately respond to NBC News’ request for comment. Sue Gough, a spokesperson for the Pentagon, declined to comment.

A spokesperson for NASA said one of the agency’s key goals was the search for life in the universe but that it had yet to find signs of extraterrestrial life.

“Although we have yet to find signs of extraterrestrial life, NASA is exploring the solar system and beyond to help us answer fundamental questions, including whether we are alone in the universe,” the spokesperson said in a statement.

Eshed’s ideas are spelled out in more detail in “The Universe Beyond the Horizon — conversations with Professor Haim Eshed” by Hagar Yanai published in November.