Relations between Taipei and Beijing have deteriorated since President Tsai Ing-wen was elected in 2016, as her government refuses to acknowledge that Taiwan is part of "one China".

Live-fire drills began Monday with troops simulating surprise air and coastal assaults to reflect increased military threats from China, which sees Taiwan as a renegade province to be brought back into the fold -- by force if necessary.

Tsai watched Thursday's session of the ongoing "Han Kuang" (Han Glory) exercise involving 4,100 soldiers, attack helicopters and fighter jets from an air base in Taichung.

Thursday's scenario simulated the enemy bombing of an airfield and a paratrooper attack, with air and ground troops deployed to take back the base.

An F-16 fighter flew overhead and deployed flares in a defensive move against heat-seeking missiles. Special operations troops were seen moving to secure a building.

"I have seen our troops' capabilities and I have faith that our troops can achieve the goal of 'solid defence and multiple deterrence'," Tsai said.

China held its own live-fire drills in April in the Taiwan Strait -- the narrow waterway separating the Chinese mainland from Taiwan -- following weeks of air and naval manoeuvres in the area.

Beijing has also stepped up diplomatic pressure on Taipei, luring four countries to switch allegiance from Taiwan to China since Tsai took office.

On Monday, the pilot of an F-16 jet involved in the drills was killed after crashing into a mountain in northern Taiwan.

The cause of the incident was under investigation.