The presidents of the United States and China, Joe Biden and Xi Jinping respectively, are set to talk for the first time in four months on a wide range of bilateral and international issues, but a possible visit to Taiwan by the speaker of the House of Representatives , Nancy Pelosi, hangs over the conversation scheduled for Thursday.China has warned that there will be a strong response if she travels to the self-governing island that Beijing claims as part of her territory.In recent years, a cabinet member and several former top US officials have visited Taiwan, but Pelosi's status as speaker of the house and second in line for presidential succession places her in a special category.In her more than three decades in Congress, the Democratic leader has stood out for her confrontational positions with China.The Chinese Foreign Ministry on Wednesday declined to comment on the presidential phone call, but spokesman Zhao Lijian reiterated Chinese warnings about Pelosi's eventual visit."If the United States insists on going its own way and challenging China's basic positions, there will certainly be strong responses," Zhao said at his daily press conference.“The subsequent consequences will fall on the United States.”Pelosi's office has not said when she will make the visit or even if she will, but it is a particularly sensitive time amid rising tensions between Beijing and Washington over trade, human rights and Taiwan.Although Biden has no authority to prevent Pelosi's visit, China's communist authoritarian government has chosen to ignore the separation of powers in the United States and says that Congress is accountable to the government.As perceived by Beijing, the fact that they are both Democrats reinforces the notion that Pelosi is working with the endorsement of Biden.Despite this, Biden told the press last week that the military command considers that "it is not a good idea" for the head of the legislative branch to visit the island at this time.The Financial Times newspaper reported last week that Pelosi planned to visit Taiwan in August, a trip initially scheduled for April, but was postponed when she tested positive for COVID-19.