China will resolutely fight back against any interference in Hong Kong affairs by foreign governments, organizations or individuals, a mainland official warned on Thursday.

Xie Feng, commissioner of the Foreign Ministry in the Hong Kong Special Administrative Region, said at the 2019 Colloquium on International Law held in Hong Kong that the SAR is facing the most dangerous and gravest situation since its return in 1997.

Some countries' gross interference in Hong Kong affairs, which are China's domestic affairs, violates international law and basic norms governing international relations, Xie said, adding they aim to damage Hong Kong's prosperity and stability and China's national sovereignty and security.

China has labeled some politicians of the United States as the "black hand" behind the anti-China rabble-rousers in Hong Kong, urging them to stop meddling in Hong Kong affairs and interfering in China's internal affairs.

In response to the remarks of some US lawmakers, including Speaker of the House Nancy Pelosi and US Senator Mitch McConnell, on the Hong Kong issue, the commissioner's office said in an online statement on Thursday that relevant US politicians have colluded with the extremists and radical forces in Hong Kong and brazenly committed wicked anti-China acts and damaged the SAR.

Abdul-Khaliq Mahjoub, a Sudanese political expert, warned against ill-grounded foreign intervention in Hong Kong affairs.

Some countries did not hide support for the negative developments in Hong Kong, while others are publicly seeking to ignite tension in the region with the belief that the move would weaken China, he said.

The expert said the entire world must be aware that tension in the special administrative region will not benefit any party, stressing the importance of ending the violence and restoring stability to Hong Kong.

Xie said the essential problem in Hong Kong now is not about human rights, freedom or democracy as some claim.

"It is about the attempt by certain violent extremists to coerce those who do not know the truth and ramp up violent crime on the pretext of opposing the amendment of the extradition bill," he said.

The violent crimes by some radical demonstrators have gone beyond the limits of law, morality and humanity, Xie stressed, highlighting the urgent need to stop violence, end the chaos and restore order in the city.

Kim Jin-ho, a professor of politics and diplomacy at Dankook University in the Republic of Korea, said the acts of violence and chaos do not serve the interests of Hong Kong people.

They should solve the problem through close communication and legal procedures, instead of using violence and illegal measures, which is dangerous, Kim said.

Xinhua contributed to this story.