A suspected Chinese spy balloon has been flying over the United States for a couple of days, U.S. officials said on Thursday, in what would be a brazen act just days ahead of a planned trip to Beijing by U.S. Secretary of State Antony Blinken.

Fighter jets were mobilized but military leaders advised U.S. President Joe Biden against shooting the balloon out of the sky for fear debris could pose a safety threat, advice Biden accepted, U.S. officials said.

The United States took "custody" of the balloon when it entered U.S. airspace and had observed it with piloted U.S. military aircraft, one of the officials told reporters on condition of anonymity.