A US fighter jet has shot down an unidentified high-altitude object over Alaska that was the size of a small car but the nature, purpose or origin of the object remains unclear. US officials said the targeted aircraft brought down on Friday was considerably smaller than the Chinese balloon downed last Saturday over the Atlantic, and carefully avoided characterising it as a balloon, drone or plane, giving nothing away about the description of the object other than its rough size, its altitude and its direction of travel. John Kirby, the spokesman for the national security council, said the pilot of the F-22 Raptor fighter which fired the missile that brought down the object judged it to be unmanned. A salvage effort is under way off the Alaskan coast near the Canadian border to recover debris from the object, involving the navy, coast guard and FBI. “The president ordered the military to down the object,” Kirby said. Unlike with the balloon which was shot down on Saturday following an eight-day trip across North America, the origins of this aircraft could not be estimated, he said. “We don’t know who owns this object,” Kirby said. The Pentagon spokesman, Brig Gen Pat Ryder, told reporters that the object had been travelling at an altitude of 40,000ft (12,190 meters), which is about the same altitude as jet airliners, so – unlike the Chinese balloon – it was quickly seen as a threat to civilian air traffic. Alaskan airspace was temporarily closed. Ryder said the object was first spotted on Thursday, and US warplanes were launched to intercept and examine it. It was shot down at 1.45pm Washington time on Friday by an AIM-9X Sidewinder heat-seeking missile fired from an F-22 fighter which took off from Elmendorf airbase near Anchorage. “The object was about the size of a small car so not similar in size or shape to the high-altitude surveillance balloon that was taken down off the coast of South Carolina on February 4,” Ryder told reporters. ABC News quoted a US official as describing the object as “cylindrical and silver-ish gray” and giving the appearance of floating. Asked if it was “balloon-like”, the official said: “All I say is that it wasn’t ‘flying’ with any sort of propulsion, so if that is ‘balloon-like’ well – we just don’t have enough at this point.” Meanwhile, Ryder said the marine salvage effort off the South Carolina coast for the Chinese balloon had made progress. “While I won’t go into specifics due to classification reasons, I can say that we have located a significant amount of debris so far that will prove helpful to our further understanding of this balloon and its surveillance capabilities,” he said. China has insisted that the downed balloon was for meteorological purposes and has denounced the US decision to shoot it down as an excessive use of force. The US insists that it was a surveillance balloon, and that an inspection of its payload by a U2 spy plane while it was still in the air, showed antennae and other equipment for intercepting and geolocating communications in the US. Late on Friday, the US Department of Commerce announced that it had blacklisted six Chinese companies for supporting Beijing’s military modernization efforts, particularly relating to aerospace programs. Companies added to the entity list are restricted from accessing US items and technologies without government authorization. China’s use of high-altitude balloons “violates our sovereignty and threatens US national security”, said Alan Estevez, the undersecretary of commerce for industry and security. “Today’s action makes clear that entities that seek to harm US national security and sovereignty will be cut off from accessing US technologies.”