WASHINGTON, Feb 15 (Reuters) - U.S. officials believe 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 U.S. 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 U.S. military off the coast of South Carolina on Feb. 4.

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

U.S. 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.

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