China is resolute in safeguarding its national sovereignty and will never allow any room for "Taiwan independence" forces in whatever form, senior envoys said.

"The one-China principle is the basic principle for China to establish and develop diplomatic ties with other countries. So it must always be observed," Zheng Zeguang, China's ambassador to the United Kingdom, said on Saturday.

"At present, the biggest threat to peace and stability in the Taiwan Straits comes from the obdurate secessionist activities of the 'Taiwan independence' forces and the connivance and support of external forces," Zheng said in a video message celebrating the 95th anniversary of the founding of the People's Liberation Army.

"We will never allow any room for 'Taiwan independence' forces in whatever form. No one should underestimate the great resolve, firm will and strong capability of the Chinese people in defending national sovereignty and territorial integrity," he said.

China is always a defender of world peace and a contributor to global development, and it upholds the international order. The PLA is a staunch force firmly committed to maintaining regional stability and promoting world peace, he added.

Geng Shuang, China's deputy permanent representative to the United Nations, also reiterated on Friday China's resolve in safeguarding its national sovereignty.

"No one should underestimate the determination and ability of more than 1.4 billion Chinese people to defend its national sovereignty and territorial integrity. I hope the country concerned will see this clearly and not play with fire," he said during a Security Council briefing on Ukraine.

The envoys' remarks came as tensions between China and the US have risen recently amid reports that US House Speaker Nancy Pelosi was considering a visit to Taiwan. China says the visit would be a violation of the US' commitment to not developing official exchanges with the island, which is an integral part of China.

China firmly opposes separatist moves toward "Taiwan independence" and interference by external forces, and never allows any room for "Taiwan independence" forces in whatever form, President Xi Jinping told US President Joe Biden during their phone conversation on Thursday.

During the briefing, Geng said the Ukraine crisis shows the importance of upholding the UN Charter, "with words matching deeds, instead of saying one thing while doing another, not to mention double standards or selective application".

"While some country has repeatedly emphasized the principle of sovereignty over the issue of Ukraine, it has incessantly challenged the sovereignty of China over Taiwan and even deliberately created tensions in the Taiwan Straits," Geng said. "This disregards and is an infringement of the purposes and principles of the UN Charter."

The envoy emphasized that "only by attaching importance to the security of others and safeguarding the security of everyone, can our own security be truly realized".

"All countries should uphold a common, comprehensive, cooperative and sustainable security concept, attach importance to each other's legitimate security concerns, build a balanced, effective and sustainable global and regional security architecture, and jointly safeguard world peace," he said.

Geng said that at a time when the international community is in dire need of unity and cooperation to overcome difficulties together, "it is extremely irresponsible and dangerous to cling to the Cold War mentality and bloc politics".

"We must not let the crisis of Ukraine kick off a new Cold War. We must not repeat the mistakes of history. We must not let humanity experience once again the unbearable scourge of war," he said.