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.

The size and scale of a recent Chinese military deployment is “unheard of,” says a diplomat in the region. Beijing, which views Taiwan as its own territory, says it is defending its sovereignty.

The assessment contrasted with statements from Taiwan that described the deployments as the largest in nearly three decades. "The PRC military activity is elevated in the region, consistent with levels we have seen during other large exercises,

Taiwan is raising concerns about a massive deployment of Chinese naval ships and military planes in the past 24 hours, saying the build-up could eventually lead to war.