Three flying objects were downed over North America in as many days and another was reportedly spotted over a Chinese port city, showing how "unidentified aerial phenomena” are keeping the world on edge since entering the international mainstream last week.

U.S. fighter jets brought down objects over Alaska and Canada on Friday and Saturday, and another was taken down on Sunday over Lake Huron in Michigan. While the administration of U.S. President Joe Biden said the high-altitude craft brought down on Feb. 4 was a Chinese spying balloon, details on the latest objects remain sparse.

With shootdowns over the U.S. and Canada coming at a pace of one per day, the incidents prompted renewed pledges by lawmakers in Washington to seek greater U.S. readiness against the overflights and a measure of bipartisan praise for the Biden administration’s military actions.