Chinese Vice President Xi Jinping took part in a congratulatory event marking the 20th anniversary of diplomatic ties between South Korea and China on Friday.

The event was hosted by the South Korean Embassy in China and the Chinese People’s Association for Friendship with Foreign Countries. Also on hand were Foreign Minister Yang Jiechi and head of the Chinese Communist Party’s international department Wang Jiarui.

Xi was the highest-ranking official among Chinese leaders who have taken part in the annual event so far, with experts interpreting his attendance as China’s willingness to improve ties with South Korea.

The celebration had been scheduled to be held at a hotel in Beijing, but was later moved to the Great Hall of the People in Tiananmen Square at the request of the Chinese government.