Until now, North Koreans in Russia were most commonly thought of as the grinding slave labourers who built soccer stadiums across the vast nation when the country hosted the 2018 World Cup.

But Vladimir Putin's comments on Thursday at the end of the BRICS Summit in Kazan, Russia, appeared to have bestowed a new, elevated status on North Korea and especially its military — that of an important ally — with its soldiers potentially fighting side by side with Russians against Ukraine.

Putin did not explicitly acknowledge that there are now North Korean troops on the ground in Russia preparing to enter the war. But most observers are taking his non-denial in response to a journalist's question about photographs taken by satellite as confirmation.

"Images are a serious thing. If there are images [of North Korean troops], then they reflect something," said the Russian president.

He then added that the two nations had just signed and ratified a strategic agreement, and "what we will do and how we will do it is up to us."

Ambiguous response

For more than a week after Ukrainian intelligence first raised the alarm that up to 12,000 North Korean troops were preparing to join the war, both American and Russia officials danced around the question, preferring ambiguity to openly acknowledging a significant escalation.

WATCH | U.S. defence secretary says there's evidence of North Koreans fighting for Russia:

'There is evidence' of North Korean troops in Russia, U.S. defence secretary says

U.S. Defence Secretary Lloyd Austin said Wednesday that it's not yet clear what exactly North Korean troops are doing in Russia.

Russia launched a full-scale invasion of Ukraine in February 2022. While both sides have relied heavily on weapons and ammunition supplied by allies, and used thousands of foreign mercenaries, this would be the first time that a foreign country has lent its ground troops to the fight.

Precisely what the North Koreans will be doing remains unclear. 

In a statement on Thursday, Ukraine's main intelligence service indicated up to 3,000 personnel had already been sent to the Kursk area, where Ukraine captured hundreds of kilometres of Russian territory over the summer. 

Other video has surfaced purportedly showing North Korean soldiers receiving Russian military fatigues and gear at a base in the country's far east.

"Twelve thousand troops could be only the beginning. This is a number that could increase and multiply many times," said Alina Frolova, a former Ukrainian deputy minister of defence who's now an analyst with the Center for Defence Strategies in Kyiv. 

"We don't know the capability and quality of those forces, and while they may not be extremely effective, they can cause some trouble," she told CBC News in an interview.

More than two and half years after Russia's invasion, both sides are facing acute shortages of manpower.

U.S. estimates suggest more than 115,000 Russian soldiers have been killed, with as many as half a million injured. The same U.S. officials reportedly believe Ukrainian casualty figures are roughly half of Russian losses.

Russian tactics in Ukraine have increasingly been likened to a "meat grinder", relying on enormous infantry assaults, rather than on mobility and technology, to try to take out Ukrainian positions. 

Huge army

North Korea is estimated to have one of the world's largest militaries, and while it has not fought a war in decades, with 1.3 million soldiers in uniform it would appear to have a vast reservoir of manpower to lend to Russia.

Beyond Ukraine, the larger implications of the pact between Vladimir Putin and North Korea's unpredictable dictator Kim Jong-un could have far-reaching implications. 

"Kim's decision to send troops to Russia is not just based on immediate economic and military-technology considerations," said Rachel Minyoung Lee, a senior fellow at the Stimson Center's Korea Program in Washington, D.C.

"He cannot have taken the step of sending his own people to Russia as mercenaries unless he had a more strategic goal in mind."

There's been widespread speculation that Putin has offered to trade Russian technology — possibly even nuclear weapons know-how — in exchange for North Korean help, although there is no proof of that, said Minyoung Lee.

"We do not know what Putin promised, but one thing seems clear: since North Korea is now directly participating in Russia's war, Kim can probably count on Russia's military involvement in case of a military conflict on the Korean peninsula," she told CBC News.

"This will obviously have a direct impact on the security landscape on and around the Korean peninsula." 

In recent weeks, tensions between North and South Korea have soared once again, with Kim Jong-un's regime claiming the U.S. strategic nuclear arsenal poses a severe threat, thereby demanding the North step up its own arsenal of ballistic missiles and nuclear weapons.

Putin's calculation

Samuel Greene, a Russia expert at King's College London, says Putin himself may be unsure where the new pact between the two countries will lead. 

"I don't think you can argue that he's doing this because everything is going swimmingly right. He's facing very real challenges," Greene said. "He is doing it, I think, relatively tentatively. There is an experimental nature to this, and he and everybody else will learn as they proceed whether or not it works."

While the reaction to the North Korean deployment within Ukraine has been one of alarm, the absence of a strong response from Ukraine's partners has been notable, says Frolova.

"There is complete silence," she said. "You need to react somehow, but there are no easy instruments you can use."

Both North Korea and Russia are already heavily sanctioned by Western countries and NATO has ruled out sending ground troops to help Ukraine. In a social media post on the North Korean developments, Ukrainian President Volodymyr Zelenskyy underscored his frustration with the country's key allies.

"If North Korea can intervene in a war in Europe, it's obvious that there hasn't been enough pressure on this regime,"  wrote Zelenskyy on X. "Aggressors must be stopped. We expect a firm, concrete response from the world. Hopefully, not just in words."

There has been no indication that Western policies will change because of this latest escalation, with most nations issuing statements of condemnation but doing little else.

"Canada is gravely concerned that North Korean troops were deployed to Russia, which contravenes UN Security Council resolutions," said a statement from Global Affairs.

American officials said if North Korean troops engage with Ukrainian forces, they would be "fair game."

South Korea's response

Perhaps the strongest reaction thus far has come from South Korea, whose officials are now openly musing about providing weapons and armaments to Ukraine. 

"The South Korean government keeps talking about 'not sitting by idly' and has hinted at the possibility of providing lethal weapons directly to Ukraine," said Minyoung Lee. "But it has been saying this since the signing of the new [North Korea]-Russia treaty in June. This tells you that it is not easy for Seoul to take this decisive step, either."

While South Korean companies do significant commercial business selling weapons, its government has historically been reluctant to supply weapons directly to countries at war.

Minyoung Lee says involving China may be the best approach for Ukraine's allies.

"I think the best option the United States and the West have at this point is to weaken the North Korea-Russia alliance, perhaps by working through China to exert pressure on Russia."

While the impact of North Korea's ground forces remains to be seen, there is no doubt that its ongoing shipments of weapons and munitions to Russia have been substantial. Earlier this year, South Korea's military said the North had shipped more than four million rounds of ammunition, effectively keeping Putin's war machine going. 

In contrast, Western supplies of items such as artillery shells have been more limited. 

"We have received less than one million rounds from our partners," said Frolova. 

While North Korea's totalitarian regime is often mocked for being isolated and backwards in the West, Russians may be prone to see it in a new light, she said.

"For internal audiences, [using North Korean troops] is a plus, not a minus," said Frolova. "It shows that Russia has partners and allies in this war against the West, and it increases their reputation."