Taiwanese voters are deciding whether to remove about one-fifth of their lawmakers from the opposition Nationalist Party.

The vote has coincided with efforts by Beijing to raise its military and diplomatic pressure on Taiwan. China has for decades claimed sovereignty over Taiwan and has never renounced the possible use of force to annex the self-governing island and unify it with the Chinese mainland.

The independence-leaning ruling Democratic Progressive Party won the last presidential election, but the China-friendly Nationalists and the Taiwan People's Party have enough seats to form a majority bloc.