A Chinese balloon that was shot down after crossing the continental United States originally had a trajectory that would have taken it over Guam and Hawaii but was blown off course by prevailing winds, a US official speaking on condition of anonymity said on Wednesday.

The balloon, which Washington accuses Beijing of using for surveillance and China says was a civilian research vessel, drifted across Alaska’s Aleutian Islands, then Canada and the central United States before it was shot down by the US military off the coast of South Carolina on Feb. 4.

The incident has further strained US-China relations and prompted US Secretary of State Antony Blinken to postpone a planned visit to Beijing last week.

US military and intelligence agencies tracked the balloon from when it lifted off from Hainan Island near China’s south coast, the Washington Post reported on Tuesday.

During a regular briefing on Thursday, Chinese foreign ministry spokesperson Wang Wenbin did not answer a question about whether the balloon was intended to fly over Guam and Hawaii before it was blown off its trajectory, instead repeating the Chinese position that the United States should not “overreact”.

The US military said on Monday it had recovered critical electronics from the balloon as well as large sections of the vessel itself.