US President Donald Trump said he is not worried about Beijing's military drills around Taiwan, choosing instead to highlight his rapport with his Chinese counterpart Xi Jinping.

I have a great relationship with President Xi, and he hasn't told me anything about [the drills]. I certainly have seen it, Trump told reporters at a press conference on Monday.

No, nothing worries me. They've been doing naval exercises for 20 years in that area, he said.

The two-day war games kicked off on Monday, nearly two weeks after the US announced one of its largest-ever arms sales to Taiwan. The sale had angered Beijing, which sees the self-governed island as a breakaway province.

China's military exercises on Tuesday will involve 10 hours of live-firing exercises in the sea and airspace surrounding Taiwan, with its Eastern Theater Command stating it has lined up various military assets for testing capabilities.

The drills, which simulate the seizure and blockade of key areas around Taiwan, have been described by the Chinese military as a warning against "Taiwan independence separatist forces" and "external interference."

Taiwan's presidential office criticized the drills as a challenge to international norms. China has maintained its long-standing goal of "reunification" with Taiwan, not ruling out the use of force to achieve this.

While Trump has downplayed the threat of Beijing's military activities, his administration recently announced an $11 billion weapons package to Taiwan, which includes advanced military equipment.

The US maintains formal ties with Beijing rather than Taiwan but acts as a significant ally and arms supplier to the island.

In response to the arms sale, China imposed sanctions on several US defense firms, asserting that any attempt to contain it using Taiwan will ultimately fail.