The White House has responded to two petitions asking the U.S. government to acknowledge formally that aliens have visited Earth and to disclose any intentional withholding of government interactions with extraterrestrial beings.

"The U.S. government has no evidence that any life exists outside our planet, or that an extraterrestrial presence has contacted or engaged any member of the human race," Phil Larson from the White House Office of Science and Technology Policy reported on the WhiteHouse.gov website."In addition, there is no credible information to suggest that any evidence is being hidden from the public’s eye."

The petition calling on the government to disclose any knowledge of or communication with extraterrestrial beings was signed by 5,387 people, and 12,078 signed the request for a formal acknowledgement from the White House that extraterrestrials have been engaging the human race.

“Hundreds of military and government agency witnesses have come forward with testimony confirming this extraterrestrial presence,” the second petition states. “Opinion polls now indicate more than 50 percent of the American people believe there is an extraterrestrial presence and more than 80 percent believe the government is not telling the truth about this phenomenon. The people have a right to know. The people can handle the truth.”

These petitions were sparked by an Obama administration initiative called "We the People." Initially, the White House said staffers would respond and consider taking action on any issue that received at least 5,000 online signatures within 30 days. The requirement has since been raised to 25,000 signatures.

Larson stressed that the facts show there is no credible evidence of extraterrestrial presence here on Earth. He pointed out that even though many scientists have come to the conclusion that the odds of life somewhere else in the universe are fairly high, the chance that any of them are making contact with humans are extremely small, given the distances involved.

"However, that doesn't mean the subject of life outside our planet isn't being discussed or explored," Larson wrote.

Larson mentioned that a scientific search for extraterrestrial intelligence is keeping an “ear” out for signals from alien civilizations, with none found so far. (He noted that this at first was a NASA effort, but is now being funded privately.)

He added that the Kepler spacecraft is searching for Earthlike planets in the habitable zones around other stars, and that the Curiosity rover will launch to Mars this month to "assess what the Martian environment was like in the past to see if it could have harbored life."

Regarding any evidence for alien life, all anyone has now is "statistics and speculation," Larson said. "The fact is we have no credible evidence of extraterrestrial presence here on Earth."

The Paradigm Research Group, one of the organizations promoting the petitions, said that the response by a "low-level staffer" was unacceptable and that it would begin a new petition campaign.

More about aliens:

See the petitions and the response at the WhiteHouse.gov website. Hat tip to NASA Watch.

This report originally appeared on the Universe Today website as "No Alien Visits or UFO Coverups, White House Says." It was supplemented by msnbc.com with the Paradigm Research Group's response.