China has simulated precision strikes against key targets on Taiwan and its surrounding waters during a second day of military drills.

The drills – which Beijing has called a “stern warning” to the self-governing island – are a response to Taiwan’s president visiting the US last week.

As the Chinese military simulated an encirclement of the island, the US urged China to show restraint.

Taiwan said at least 71 Chinese jets flew around the island on Saturday.

Taiwan also said 45 warplanes either crossed the Taiwan Strait median line – the unofficial dividing line between Taiwanese and Chinese territory – or flew into the southwestern part of Taiwan’s air defence identification zone.

Nine Chinese ships were also spotted. The operation, dubbed “Joint Sword” by Beijing, will continue until Monday. Taiwanese officials have been enraged by the operation.

On Saturday defence officials in Taipei accused Beijing of using President Tsai’s US visit as an “excuse to conduct military exercises, which has seriously undermined peace, stability and security in the region”.

A state department spokesperson said the US was “monitoring Beijing’s actions closely” and insisted the US had “sufficient resources and capabilities in the region to ensure peace and stability and to meet our national security commitments”.

US President Joe Biden has said on several occasion that the US would intervene if China attacked the island, but US messaging has been murky.

Taiwan’s status has been ambiguous since 1949, when the Chinese Civil War turned in favour of the Chinese Communist Party and the country’s old ruling government retreated to the island.

Taiwan has since considered itself a sovereign state, with its own constitution and leaders. China sees it as a breakaway province that will eventually be brought under Beijing’s control – by force if necessary.

China’s President Xi Jinping has said “reunification” with Taiwan “must be fulfilled”.