Police officers across the US have been issued a handbook on how to deal with reports of ‘unidentified anomalous phenomena’ (UAP).

The guidelines, which detail several past encounters, were sent out earlier this summer by the Major Cities Chiefs Association (MCAA), which represents police executives from the largest cities in the US and Canada.

In the 11-page guide, the MCAA notes that UAPs detected in US airspace represent a “domain awareness gap” which poses a “clear and present danger to pilots and our soldiers that is more acute than ever.” It also cites reports by several government agencies, such as the Office of the Director of National Intelligence, concluding that such phenomena are also a “clear threat to national security, since their capabilities and origins are unknown.”

The handbook provided details on several UFO investigations, and cited the testimonies of whistleblowers who have been involved in such incidents, such as former US Air Force officer and intelligence official David Grusch.

In one Congressional hearing on UAPs, Grusch claimed he had interviewed several Pentagon officials with direct knowledge of aircraft that were of “nonhuman” origin, who reported that so-called “biologics” were recovered from some of the craft.

The document also recalled the testimonies of US Navy pilots Ryang Graves and David Fravor, who described encountering UAPs on training missions. Fravor was the pilot that spotted and recorded the famous ‘Tic Tac’ UFO during a flight near California in 2004.

The booklet also provides several stories shared by officers who had encountered unknown aircraft while on duty.

One officer’s report claimed that he had once seen a triangular UFO in the sky with three dim green lights while driving in his patrol vehicle. He stressed that he was aware of what helicopters and airplanes looked like in the sky, and that what he saw was “unlike anything I had ever witnessed.”

Within an hour after the encounter, the officer claims to have responded to a call from a homeowner in the area that reported “something running outside of his home” which “did not sound like an animal.”

The MCAA guidebook concludes by providing a number of links to various UAP reporting websites, and encouraging police officers to report any bizarre incidents and sightings. At the same time, it is noted that the document does not represent the opinions of policies of the MCAA and is intended to share information collected from open sources. [Handbook]