HONG KONG – North Korean troops will fight alongside Russian forces as early as this weekend, Ukraine said Friday. This adds new urgency to a stunning turn in the war that has worried the Kremlin's enemies but could also cause headaches for its friends.

Reports confirmed by Washington this week that North Korea is sending soldiers to Russia to potentially fight Ukraine have sparked widespread concern among the United States and its allies. They say their involvement represents a significant escalation in the bitter conflict and could exacerbate security risks for North Korea's neighbors.

It is also likely to be unwelcome news for China, which has long been North Korea's most important ally but whose influence over the reclusive nuclear state is being undermined by leader Kim Jong Un's growing relationship with President Vladimir Putin.

For Beijing, the troop build-up from Pyongyang is the latest and most alarming sign of Moscow's abuses.

“I think it makes them very uncomfortable,” said Ian Bremmer, founder and president of Eurasia Group, a New York-based consulting firm.

“If the North Koreans are actually sending troops to fight with the Russians, then clearly the level of Russian willingness to support North Korea and help defend North Korea will be equivalent,” he said in an interview with NBC News on Thursday. “And that in many ways actually replaces China as North Korea’s primary protector.”

Ukraine says North Korean troops in Russia could join the fight starting Sunday

The United States and its ally South Korea say 3,000 North Korean troops have been sent to Russia, with the total expected to reach 12,000.

Ukrainian President Volodymyr Zelensky said this in a statement on Friday Post on X that the first North Korean soldiers should be stationed in combat areas as early as Sunday. It would be the North Korean military's first large-scale overseas deployment since the Vietnam War.

Ukraine said on Thursday that the first North Korean troops were already stationed in the Russian border region of Kursk, where Ukrainian forces launched an incursion in August.

The video released last week by the Ukrainian government's Center for Strategic Communications and Information Security purports to show North Korean soldiers being equipped with Russian military equipment in the Russian Far East. NBC News has not independently verified the date or location of the video in which people can be heard speaking Korean.

The deployment of North Korean troops would not only give Putin a boost on the battlefield but also further strengthen his partnership with Kim, who signed a pact in Pyongyang in June that includes a mutual defense pledge.

Putin did not deny that North Korea was sending soldiers to Russia and initially resorted to sarcasm when NBC News asked about it on Thursday, saying it was up to the two countries to decide how to implement the agreement.

“We are in contact with our North Korean friends. We will see how this process develops,” he said while hosting the BRICS summit in Kazan, Russia. He added that it was the United States and other Western countries that escalated the war in Ukraine.

A North Korean official at the United Nations in New York said on Monday that reports of North Korean soldiers being sent to Russia were “baseless rumors.”

South Korea said on Friday it was “deeply concerned” after the mutual defense pact was ratified by the lower house of Russia's parliament a day earlier and the upper house was expected to follow shortly.

South Korean Defense Minister Kim Yong-hyun and his US counterpart Lloyd Austin will hold their annual meeting in Washington next week. South Korean officials said Friday that the two men will discuss how the North Korean deployment could affect the security situation on the Korean peninsula.

Tensions there have increased as North Korea, still technically at war with the South, continues to advance its weapons programs and issue threats.

The United States and other countries say Moscow could provide Pyongyang with key military technology for these programs in exchange for munitions needed in Ukraine, including millions of artillery shells. Both North Korea and Russia deny any arms transfer.

But experts say the agreement could make Moscow even more committed to Pyongyang and potentially more willing to share the technologies and expertise most coveted by North Korea.

The entry of North Korean troops into the Ukraine war could also lead to a further escalation of the conflict.

South Korea is now considering expanding its support to Ukraine from non-lethal aid to defensive and perhaps even offensive weapons. The government of Japan, another U.S. ally directly threatened by North Korea's weapons programs, said Friday it was monitoring the situation “with great concern.”

China, which borders both North Korea and Russia and is growing closer with both countries to challenge the U.S.-led international order, has its own reasons to worry.

It has tried to portray itself as neutral in the Ukraine war by putting forward a peace plan that Ukraine, the United States and others say is too favorable to Russia. But China has supported Russia diplomatically and economically, and the United States accuses the country of supplying Russia with dual-use technology, which it denies.

Beijing is not particularly satisfied with either North Korea's recent behavior or the direction of the war in Ukraine, Bremmer said.

He noted that Chinese President Xi Jinping had called for an end to the Ukraine war in a speech at the BRICS summit this week.

“I honestly think North Korea’s move is a big part of it,” Bremmer said.

Asked about the reported North Korean deployment on Thursday, a Chinese Foreign Ministry spokesman said Beijing was not aware of the situation.

“China's position on the Ukraine crisis has been consistent and clear, and it hopes that all parties will work towards de-escalating the situation and continue to advocate for a political solution,” spokesman Lin Jian said at a regular briefing in Beijing.

Bremmer, who met with Chinese Foreign Minister Wang Yi and other senior Chinese leaders in Beijing last week, said he felt they were “undermined” by relations with Russia and the course of the war in Ukraine, which began weeks after Xi. are clearly unpleasant” and Putin declared a “borderless” partnership in Beijing in February 2022.

“They said things like, 'Well, the Kremlin told us this would happen in a few weeks,' and that's not the case,” Bremmer said. “In other words, they sold them a bill of materials, so to speak.”

Although the Chinese government has so far appeared largely unwilling to use its influence over Russia in Ukraine, Bremmer said it is now actively considering “taking a more assertive stance, perhaps more willing to work with the Americans and others after the election.” “To try to end the war.”