TAIPEI: China's launched unprecedented live-fire military drills in six areas that ring Taiwan on Thursday, a day after a visit by U.S. House of Representatives Speaker Nancy Pelosi to the self-ruled island that Beijing regards as Chinese territory.

Soon after the scheduled start at 0400 GMT, China's state broadcaster CCTV said the drills had begun and would end at 0400 GMT on Sunday. They would include live firing on the waters and in the airspace surrounding Taiwan, it said. 

Taiwan officials have said the drills violate United Nations rules, invade Taiwan's territorial space and are a direct challenge to free air and sea navigation.

China is conducting drills on the busiest international waterways and aviation routes and that is "irresponsible, illegitimate behaviour," Taiwan's ruling Democratic Progressive Party (DPP) said.

Taiwan's cabinet spokesman, expressing serious condemnation of the drills, said also that websites of the defence ministry, the foreign ministry and the presidential office were attacked by hackers.

On Wednesday night, just hours after Pelosi left for South Korea, unidentified aircraft, probably drones, flew above the area of Taiwan's outlying Kinmen islands near the mainland coast, Taiwan's defence ministry said. 

Major General Chang Zone-sung of the army's Kinmen Defense Command told Reuters that the drones came in a pair and flew into the Kinmen area twice on Wednesday night, at around 9 p.m. (1300 GMT). and 10 p.m.

"We immediately fired flares to issue warnings and to drive them away. After that, they turned around. They came into our restricted area and that's why we dispersed them," he said.

China, which claims Taiwan as its own territory and reserves the right to take it by force, said on Thursday its differences with the self-ruled island were an internal affair. 

"Our punishment of pro-Taiwan independence diehards, external forces is reasonable, lawful," China's Beijing-based Taiwan Affairs Office said.

Unusually, the drills in six areas around Taiwan were announced with a locator map circulated by the official Xinhua news agency - a factor that for some analysts and scholars shows the need to play to both domestic and foreign audiences.

On Thursday, the top eight trending items on China's Twitter-like Weibo service were related to Taiwan, with most expressing support for the drills or fury at Pelosi.

"Let's reunite the motherland," several users wrote.

In Beijing, security in the area around the U.S. Embassy remained unusually tight on Thursday as it has been throughout this week. There were no signs of significant protests or calls to boycott U.S. products.

"I think this (Pelosi's visit) is a good thing," said a man surnamed Zhao in the capital's central business district. "It gives us an opportunity to surround Taiwan, then to use this opportunity to take Taiwan by force. I think we should thank Comrade Pelosi."

PLEDGED SOLIDARITY

Pelosi, the highest-level U.S. visitor to Taiwan in 25 years, praised its democracy and pledged American solidarity during her brief stopover, adding that Chinese anger could not stop world leaders from travelling there.

China summoned the U.S. ambassador in Beijing in protest against her visit and halted several agricultural imports from Taiwan.

"Our delegation came to Taiwan to make unequivocally clear that we will not abandon Taiwan," Pelosi told Taiwan's President Tsai Ing-wen, who Beijing suspects of pushing for formal independence - a red line for China. 

"Now, more than ever, America's solidarity with Taiwan is crucial, and that's the message we are bringing here today."

The United States and the foreign ministers of the Group of Seven nations warned China against using Pelosi's visit as a pretext for military action against Taiwan.

"Sadly, Taiwan has been prevented from participating in global meetings, most recently the World Health Organization, because of objections by the Chinese Communist Party," Pelosi said in statement issued after her departure.

"While they may prevent Taiwan from sending its leaders to global forums, they cannot prevent world leaders or anyone from travelling to Taiwan to pay respect to its flourishing democracy, to highlight its many successes and to reaffirm our commitment to continued collaboration," Pelosi added.