China warned on Thursday that “provocations” by Taiwan leader Lai Ching-te, who earlier gave a speech on the self-ruled island’s National Day, would result in “disaster” for its people.

“(Lai’s) provocations in seeking ‘independence’ are the root cause of trouble for peace and stability in the Taiwan Strait and will bring disaster to the people of Taiwan,” said Chen Binhua, a spokesman for China’s Taiwan Affairs Office.

China has not ruled out using force to bring the democratic island under its control, which Lai and his government oppose. Lai pledged in his speech to defend the island’s “national sovereignty”.

But he also said Taipei’s efforts to preserve the “status quo of peace and stability in the Taiwan Strait remain unchanged”.

Beijing has ramped up pressure on Taiwan to accept its territorial claims and relations have remained tense under Lai, who took office in May.

China’s foreign ministry spokeswoman Mao Ning told a regular news briefing that Lai’s speech “exposed his hell bent position on Taiwan independence and his sinister intention to escalate tensions in the Taiwan Strait for political self-interest”.