Hong Kong is facing its worst crisis since it returned to China from British rule in 1997, the head of China’s Hong Kong and Macau Affairs office said on Wednesday amid more anti-government protests in the Asian financial hub.

Zhang Xiaoming, one of the most senior Chinese officials overseeing Hong Kong affairs said that Hong Kong is facing its most serious threat since the city returned to Chinese sovereignty.

Zhang held a forum on Wednesday to discuss the political crisis in Hong Kong which included Hong Kong delegates to China’s parliament, the National People’s Congress and China’s main consultative body, the CPPCC. No opposition democratic figures or protest representatives were invited.

Hong Kong has seen months of sometimes violent protests that began with opposition to a now-suspended extradition law and which have evolved into a direct challenge to the government of embattled leader Carrie Lam and calls for full democracy.

Hong Kong’s protests pose a major challenge to Chinese President Xi Jinping who is grappling with a trade war with the United States and a slowing economy.