Suspected drones flew over outlying Taiwanese islands and hackers attacked its defense ministry website, authorities in Taipei said on Thursday, a day after a visit by U.S. House of Representatives Speaker Nancy Pelosi that outraged China.

China was to begin a series of military exercises around Taiwan on Thursday in response to Pelosi's visit, some of which were to take place within the island's 12-nautical-mile sea and air territory, according to the defense ministry in Taipei.

That has never happened before and a senior ministry official described the potential move as "amounting to a sea and air blockade of Taiwan."