STORY: The Biden administration has recently warned that China is "at least contemplating" giving weapons and that Washington would release more details soon. It said there would be "consequences" if China provided material support to Russia's invasion of Ukraine.

There was no immediate comment from China, but its Foreign Ministry said earlier on Thursday any potential intelligence on arms transfer by China to Russia that the United States plans to release was just speculation.

Stoltenberg told Reuters that he was concerned that history may "repeat itself" after the war ends, pointing to previous Russian military interventions in Crimea and Georgia.