U.S. House of Representatives Speaker Nancy Pelosi will meet Japanese officials in Tokyo on Friday, following a visit to Taiwan that Beijing answered with unprecedented military drills and missile launches including five that landed within Japan's exclusive economic zone.

Pelosi's brief trip to Taiwan, where she arrived unannounced with a congressional delegation late on Tuesday and left on Wednesday, marked the highest-level U.S. visit to the self-ruled island, which China claims as its own, in 25 years.

It also came as Tokyo, one of Washington's closest allies, has been increasingly alarmed about China's growing might in the Indo-Pacific and the possibility that Beijing could take military action against Taiwan.

Pelosi lauded Taiwan's democracy and pledged American solidarity. Beijing responded with military drills that a state broadcaster said would be the largest by China in the Taiwan Strait, including live firing on the waters and in the airspace around the island.

Five missiles landed in Japan's exclusive economic zone (EEZ), prompting Tokyo to lodge a strong protest through economic channels.

Japan, whose southernmost islands are closer to Taiwan than Tokyo, has warned that Chinese intimidation of Taiwan is an escalating national security threat.

Prime Minister Fumio Kishida's Liberal Democratic Party (LDP) has also pledged to double military spending to 2% of GDP.

Tensions between Japan and China ramped up a notch on Thursday when China announced that a meeting between the two nations' foreign ministers, set to take place on the sidelines of an ASEAN meeting in Cambodia, had been called off due to its displeasure with a G7 statement urging Beijing to resolve Taiwan tension peacefully.

Pelosi arrived in Japan following a visit to South Korea on Thursday, where she vowed support to denuclearise North Korea.

In Tokyo, she and Kishida met for discussions on Friday morning. She is also expected to meet her Japanese counterpart Hiroyuki Hosoda, speaker of the more powerful lower house of parliament.

While visiting Japan in May, U.S. President Joe Biden said he would be willing to use force to defend Taiwan - a comment that appeared to stretch the limits of the U.S. policy of "strategic ambiguity" towards the island.