Taiwan is on high alert in response to China’s unannounced deployment of naval and Coast Guard ships, as tensions rise over U.S. support for the island.

China’s large-scale military exercises are encircling Taiwan and testing the island’s defenses. They also raise the risk of conflict, accidental or otherwise.

Scores of Chinese aircraft and dozens of ships surrounded Taiwan, after President Lai Ching-te rejected Beijing’s claim over the island.