May 14 (UPI) -- Chinese President Xi Jinping warned U.S. President Donald Trump on Thursday that Taiwan was the "most important issue" in bilateral relations and said mishandling the matter could push the two superpowers into "conflict," as the leaders opened a high-stakes summit in Beijing.

The remarks came during the opening talks of Trump's two-day visit to China, held against the backdrop of the Iran conflict and mounting tensions over trade, technology and regional security.

Xi, however, placed Taiwan -- a self-governing island of 23 million people that China claims as its territory and has vowed to bring under its control -- at the top of the agenda.

"The Taiwan question is the most important issue in China-U.S. relations," Xi told Trump during a meeting at the Great Hall of the People, according to a readout from China's Foreign Ministry.

"If it is handled properly, the bilateral relationship will enjoy overall stability," Xi said. "Otherwise, the two countries will have clashes and even conflicts, putting the entire relationship in great jeopardy."