Washington: The military had not identified earlier spy balloons before the one that appeared over the United States on January 28. A senior U.S. general in charge of shooting down a Chinese spy balloon called it an "awareness gap" on Monday.
Chinese spy balloons have briefly flown over the United States at least three times during President Donald Trump's administration and once before, according to the Pentagon's report over the weekend.
The latest balloon was 200 feet (60 meters) tall, with a payload that weighed a few thousand pounds, according to Air Force General Glen VanHerck, who is also the commander of the United States Northern Command and the North American Aerospace Defense Command.
He omitted details about earlier balloons, such as where they flew over the United States.
"I'll admit that we missed those threats, and that indicates a domain awareness gap," said VanHerck.
Without going into further detail as to whether those "additional means of collection" of intelligence might have involved human sources, telephone intercepts, or cyber espionage, VanHerck added that U.S. intelligence discovered the earlier flights after the fact.
Senior U.S. officials have offered to brief former administration members on the specifics of earlier balloon overflights that took place while Trump was president.
The Pentagon informed Republican Representative Michael Waltz, a member of the House of Representatives intelligence committee, that several Chinese balloon incidents had occurred in recent years, including some over Florida.
A week after it first entered American airspace and set off a dramatic and widely publicized spying saga that deteriorated Sino-U.S. relations, a U.S. Air Force fighter jet shot down the suspected Chinese spy balloon off the coast of South Carolina on Saturday.
VanHerck said he had no proof of explosives being on the balloon, but he also did not rule out the possibility. However, he planned to shoot the balloon down over open water because of that risk.
Several fighter and refueling aircraft were involved in the mission, but only one fired the shot at 2:39 p.m. (1939 GMT), firing a single AIM-9X supersonic, heat-seeking air-to-air missile from Langley Air Force Base in Virginia.
The debris, according to VanHerck, had been gathered from a region measuring roughly 1,500 meters (4,920 feet) by 1,500 meters, and several military vessels had assisted in the operation.
The temporary security zone will be in place in the waters off Surfside Beach, South Carolina, where the balloon was shot down, the U.S. Coast Guard announced on Monday.
The integrity of the spying sensors carried by the balloon's payload, which could determine whether or not the shoot-down was successful in terms of gathering intelligence, was not disclosed by officials.