Russian President Vladimir Putin on Thursday appeared to confirm reports that North Korea had sent thousands of troops to eastern Russia.

It pointed to deeper ties between the two authoritarian regimes, which could extend to North Korean soldiers fighting in Ukraine.

Some analysts say North Korea's main backer, China, will be unhappy about the intensifying of relations.

"There is nothing good for them in this, short or long term," Victor Cha, a Korea expert at the Center for Strategic and International Studies in Washington, told The New York Times.

China's foreign affairs ministry on Thursday said only that it was "not aware of the relevant situation" between Russia and North Korea.

Experts told Business Insider that the bland statement could mask a situation that is in fact to China's benefit.

An authoritarian nexus

"Officially, they might not really welcome it, they might see it as an alarming situation," said Jagannath Panda, head of the Stockholm Center for South Asian and Indo-Pacific Affairs.

"But the Chinese are waiting for an opportunity where North Korea, Russia, and China can come stronger together, and I think North Korea sending the troops to Russia is a testimony to that."

Panda said that China's strategic goal is to build an authoritarian nexus that would undermine the current world order. The growing alliance between North Korea and Russia, he said, is a step toward that.

China has enough influence over both Russia and North Korea to shape their alliance, according to Sari Arho Havrén, an associate fellow at the UK's Royal United Services Institute.