Some supposed UFO sightings have been accompanied by unexplained physical evidence that deserves serious scientific study, an international panel of scientists has concluded.

In the first independent scientific review of the controversial topic in almost 30 years, directed by physicist Peter Sturrock of Stanford University, the panel emphasized that it had found no convincing evidence of extraterrestrial intelligence or any violation of natural laws.

"It may be valuable to carefully evaluate UFO reports to extract information about unusual phenomena currently unknown to science," the report stated, adding that such research could also improve understanding of, and in some cases debunk, supposed UFO events.