Chinese President Xi Jinping held a rare meeting with Cheng Li-wun, the leader of Taiwan’s largest opposition party, the Kuomintang (KMT), in Beijing on Friday, where he said China welcomes “peaceful development” across the Taiwan Strait, and called people from both countries “one family.”

This was the first official meeting between the sitting heads of the Chinese Communist Party and the KMT, which favors closer ties with Beijing, in almost a decade.

“We firmly believe that more and more Taiwan compatriots … will recognize that Taiwan’s development prospects hinge on a strong motherland, and that the interests and well-being of Taiwan compatriots are closely linked to the great rejuvenation of the Chinese nation,” Xi said, according to China’s state-run news agency Xinhua.

The meeting comes ahead of a summit in Beijing with President Donald Trump planned for May, where Xi is likely to bring up his opposition to U.S. arms sales to Taiwan – a self-governing island that Beijing claims as its own territory, and has refused to rule out taking by force.

Xi and Cheng shook hands in front of journalists at Beijing’s Great Hall of the People, where Chinese leaders have traditionally received high-profile guests.

Xi said that he was willing to work with all political parties in Taiwan to foster peaceful relations.

But Beijing has so far refused to engage with Taiwan’s governing Democratic Progressive Party as it considers its leaders to be separatists.

Taiwan is a democracy but, under pressure from Beijing, very few countries recognize it as independent.

The KMT doesn’t go as far as advocating for unification, but Cheng agrees with Beijing in opposing Taiwanese independence and said that both sides of the Taiwan Strait belong to one China.

Though each side interprets “one China” differently. A survey in April showed the KMT has less than a third of popular support.

Beijing has escalated military drills around Taiwan in recent years.

Cheng has called her trip a peace mission to show that dialogue is possible with Beijing to ease tensions.