U.S. general says past Chinese balloons flew undetected

STORY: The U.S. Coast Guard imposed a temporary security zone in the waters off South Carolina on Monday, as the military collected debris from a suspected Chinese spy balloon -- shot down by a U.S. fighter jet over the weekend.

China called the shooting down of the balloon an "obvious overreaction" and urged the U.S. to show restraint over the episode.

Outside the White House, President Joe Biden insisted on Monday that the incident had not weakened U.S.-China relations.

"No. We made it clear to China what we're going to do. They understand our position. We're not going to back off. We did the right thing. And there's not a question of weakening or strengthening. It's just reality."

REPORTER: "Has it always been your view to shoot down a Chinese spy balloon or was it only because it became public?"

BIDEN: "Oh no. It was always my position. Once it came over to the United States from Canada, I told the defense department I wanted to shoot it down as soon as it was appropriate. They concluded, they concluded we should not shoot it down over land. It was not a serious threat and we should wait until it got across the water."

The balloon led U.S. Secretary of State Antony Blinken to postpone a planned visit to China but, as of Monday, there was no update on when it might be rescheduled.

"We are... we haven't had conversations at this point about rescheduling the trip."

The White House said lines of communication would stay open but that the ball was in China's court.

"It's up to China to figure out what kind of relationship they want."

Meanwhile, Air Force General Glen VanHerck, who was responsible for bringing down the balloon, said previous spy ballons had flown undetected by the U.S. military in what he called an "awareness gap."

The Pentagon said over the weekend that Chinese spy balloons had briefly flown over the United States at least three times during President Donald Trump's administration and one previously under President Joe Biden.

VanHerck said the balloon shot down on Saturday was 200 feet tall with a payload underneath that weighed a couple thousand pounds.

VanHerck did not rule out that there could have been explosives on the balloon, but said he did not have any evidence of it either. That risk, however, was a factor in his planning to shoot down the balloon over open water.