With Japan’s new leader refusing to back down from China’s show of force and claims on Taiwan, Xi Jinping picks up the phone to try to pry the U.S.-Japan alliance apart.

In an unusual diplomatic move, Chinese leader Xi Jinping initiated a phone call with President Trump on Monday to discuss Taiwan, a flashpoint that has surged to the forefront in recent days as Japan takes a more assertive stance on the island’s autonomy.

China advised its citizens Friday to refrain from traveling to Japan in the near future. It cited earlier attacks against Chinese in Japan and what it called Prime Minister Sanae Takaichi 's "erroneous remarks" on Taiwan, which it said undermined the atmosphere for China-Japan exchange.

Taiwan Premier Cho Jung-tai said on Tuesday that a "return" to China is not an option for the island's 23 million people, after Chinese President Xi Jinping pressed his country's sovereignty claims in a call with U.

China closed off Japanese seafood imports after Japan’s new leader declared strong support for Taiwan. Suddenly, sushi is everywhere on Taiwanese social media.

Trump’s back-to-back calls with Xi and Takaichi did nothing to temper Beijing’s pressure campaign on Tokyo over Taiwan.

China is trying to impose economic costs on Japan for wading into the issue of Taiwan. But experts say the escalating dispute could ultimately hurt China too.