US House Speaker Nancy Pelosi is set to depart for Asia this weekend amid intense scrutiny over whether she would visit Taiwan following repeated warnings from Beijing . Her departure would immediately follow a phone call between presidents Xi Jinping and Joe Biden, when the Chinese leader told the US not to “play with fire” over the issue. However, one diplomatic observer said “even stronger warnings” may have been given in private, while another suggested that although China would avoid a response that directly targeted the US, its military would take action directed towards Taiwan . About half of the brief Chinese statement issued following the call was devoted to Taiwan, although it did not refer to Pelosi or her possible visit. However, Zhao Lijian, a spokesman for China’s Ministry of Foreign Affairs, told a regular press conference that “everyone knows that the call took place against the backdrop of Speaker Pelosi’s plan to visit Taiwan”. Pelosi’s team has been tight-lipped about media reports that she would visit the island during the tour, which will include stops in Japan, Indonesia and Singapore. The tour comes ahead of the symbolically important celebrations to mark the foundation of the Chinese military on Monday – a day when official messaging often emphasises the People’s Liberation Army’s sacrifices to preserve the country’s integrity. Chinese, US warships keep watch amid tensions over a Pelosi Taiwan visit It also takes place in the build up to the Communist Party’s twice-a-decade congress – a major political set piece where Xi, who has repeatedly pledged to reunify with Taiwan, is expected to secure an unprecedented third term as the party’s general secretary. “The timing is unfortunate,” said Wang Yong, an international relations professor at Peking University, “if Pelosi visits Taiwan, the consequences would be very serious and could trigger another crisis in the Taiwan Strait. “And I believe the private discussions [between Beijing and Washington] could be more heated and the warning may be stronger. Although the speaker does not have any direct responsibility for foreign affairs, as the second in line to the presidency after the vice-president, Pelosi would be the highest ranking US politician to travel to the island since her predecessor Newt Gingrich visited in 1997. Beijing has amplified its warnings over the past few days, with the Chinese Ministry of Defence warning of “forceful measures” if Pelosi visits. Global Times , a tabloid affiliated to the party mouthpiece People’s Daily, said the PLA may send warplanes to shadow Pelosi’s aircraft while Wang said the drills in the Taiwan Strait may include missile tests. Su Hao, a professor at China Foreign Affairs University, said while Beijing “may not directly target the US”, its military will be active “in and around the Taiwan Strait, as a direct deterrence to Taiwan”. He added that Beijing has shown deep caution about the Xi-Biden call. Beijing had been reluctant to confirm it would take place ahead of the conversation even though the US had issued regular briefings about what to expect. The Chinese statement issued after the two leaders spoke said that it was the US that had initiated the call, and Su said “the US side was very eager to talk to China … to ensure that [Pelosi’s possible visit] would not lead to a showdown or a breakdown between China and the US”. Japanese lawmakers visit Taiwan for talks on how to prepare for conflict He added: “Meanwhile, China certainly believed that the call was necessary, but its attitude was passive as China was waiting to see what kind of commitment the US could make before deciding whether the call could be made.” According to Beijing, Biden told Xi that the US’ one-China policy “has not changed and will not change” and Washington did not support Taiwanese independence. Meanwhile the White House also said that Biden had “underscored that the United States policy has not changed” and the US “opposes unilateral efforts to change the status quo or undermine peace and stability across the Taiwan Strait”. Beijing regards the self-ruled island as part of its territory under its one-China principle. The US recognises Beijing to be the legitimate government of China, but only acknowledges – and does not endorse – its position that Taiwan is a part of China. Beijing considers unification with Taiwan as the highest national priority and has never renounced the use of force to achieve this goal. It also regards any official contact between Taiwan and a foreign government as a violation of its sovereignty.