Los Angeles, California (CNN) --

The Pentagon is unable to explain images of what appears to be a high-altitude rocket or missile launched off the coast of southern California at sunset Monday, officials said.
The Pentagon and the North American Aerospace Defense Command were investigating video shot by a news helicopter operated by CNN affiliate KCBS/KCAL showing an ascending orange-colored contrail high into the atmosphere, officials said. A contrail is the visible vapor trail behind airplanes or rockets traveling at high altitudes.
The Federal Aviation Administration, the Coast Guard, Navy, Air Force, and California Reps. Dana Rohrabacher and Jane Harman -- whose coastal districts are closest to the offshore contrails -- were at a loss to explain the images.
"The FAA ran radar replays of a large area west of Los Angeles based on media reports of the possible missile launch at approximately 5 p.m. (PT) on Monday. The radar replays did not reveal any fast moving, unidentified targets in that area," said FAA spokesman Ian Gregor. "The FAA did not receive reports ... of unusual sightings from pilots who were flying in the area on Monday afternoon.

"The FAA did not approve any commercial space launches around the area Monday," he added.
Col. Dave Lapan, a spokesman for the Pentagon, said Tuesday morning that authorities were "still trying to find out what that contrail off the coast of southern California was caused by, whether it was commercial, whatever reasons there might be."
"Sometimes we don't find these things out in a timely manner," he added. "Right now, all indications are that it was not [Department of Defense] involvement."
Lapan said the North American Aerospace Defense Command reported that it could not provide specific details, but that various agencies are trying to find out what happened.
"I don't know specifically what they are all doing. I just know they have been pinged and that we are talking to the FAA, we are talking to other parts of the U.S. government. We are trying to do everything we can to figure out if anybody has any knowledge of what this event may have been," Lapan said in off-camera comments to journalists.
"So far we have come up empty," he added.
CNN'S Charley Keyes contributed to this report.