ISTANBUL 

China on Wednesday doubled down on its pledge to take countermeasures after a visit to Taiwan by US House Speaker Nancy Pelosi which both sides will "constantly feel."

The measures will be "resolute, forceful and effective," and will "constantly" be felt by relevant authorities in the US and Taiwan, China's Foreign Ministry spokesperson Hua Chunying told reporters in Beijing a day after Pelosi's plane touched down on the self-ruled island that Beijing claims as its own.

"The nature of US House Speaker Nancy Pelosi's visit to the Taiwan region is not about democracy, but is an issue about China's sovereignty and territorial integrity," Hua said, according to Chinese broadcaster CGTN.

"Every time the US provoked China, the result has been shame on themselves. The latest example was Pelosi instigating the black-clad riots in Hong Kong," she added.

In a press during her visit, Pelosi had said that "strength, goodwill and again, the demonstration of a democracy that has evolved to a stronger place now and offers a very strong contrast to what's happening in mainland China ... no more evidence needed than what happened in Hong Kong," referring to the semi-autonomous region which has undergone radical changes since pro-democracy protests erupted there in 2019.

Beijing's repeated threat of countermeasures against Washington comes after Pelosi defied Chinese warnings, including of military action, and went ahead with her trip to Taiwan, the first in 25 years for a sitting US Congress speaker.

She landed in Taipei on Tuesday night, holding marathon talks since this morning.

Beijing has already launched military drills near Taiwan and has planned several exercises to start on Thursday around the self-ruled island, home to over 24 million people.

"Taiwan separatists must bear responsibility and pay the price for their mistakes," Hua said, referring to the reception given to Pelosi, which China claims as its "breakaway province," while Taipei has insisted on its independence since 1949.