Xi Jinping urged Joe Biden that the United States "follow the 'one China' principle".And warned not to "play with fire" in relation to Taiwan.© Mate 3rd Class Elizabeth Thompson / Creative CommonsA US Navy aircraft carrier entered the waters of the South China Sea on Thursday, the same day that the heads of state of the two countries talked about the increase in tensions related to Taiwan.China.Xi Jinping warns Biden not to play with fireThe US Seventh Fleet said in a statement that the USS Ronald Reagan maneuver was part of a scheduled operation and that the ship left Changi Naval Base in Singapore on Tuesday.This crossing takes place at a time of tension between the two powers, due to the possible visit of the Democratic leader of the House of Representatives, Nancy Pelosi, to Taiwan.She subscribes to the Diário de Notícias newsletters and receives first-hand information.Pelosi has yet to officially announce any trips to Taiwan - a territory that Beijing claims as a breakaway province to be forcibly reunited if necessary - but the Chinese government has warned that it will respond with "strong measures" if the visit is confirmed.However, the Seventh Fleet pointed out that the ship is carrying out maritime security operations before reaching the South China Sea.These include sea and air operations, as well as coordinated tactical exercises between troops on land and in the air."The USS Ronald Reagan is on its way, operating in the South China Sea after a successful visit to Singapore," explained Commander Hayley Sims, a spokesman for the 7th Fleet."The ship continues to operate normally and routinely carries out its patrol duties to keep an open Indo-Pacific region," he added, quoted by Europa Press.The South China Sea is an area for commercial shipping, most of which is claimed by China.The Chinese and US presidents today had a "sincere and in-depth" telephone conversation, according to Chinese state media, which also advance that Xi Jinping warned Joe Biden not to "play with fire" in relation to Taiwan.China's Foreign Ministry said in a statement that Xi Jinping asked his US counterpart that the United States "follow the 'one China' principle".On the US side, the White House said so far that the two leaders talked for more than two hours about the growing tensions between Washington and Beijing, regarding the Taiwan issue and the trade disputes that exist between the two countries. .The call, which lasted precisely two hours and 17 minutes, had started at 08:33 local time (13:33, Lisbon time).It was the fifth conversation between the two leaders since Biden arrived at the White House in January 2021.Relations between the two countries began to deteriorate in 2018, when then US President Donald Trump began a trade war with China that later extended to the technology and diplomacy sector.In the last year, tensions have intensified over Taiwan, with which the US does not maintain official relations, especially since Washington is the main supplier of weapons to the island and would be its biggest military ally in the event of a war with the giant. Asian.