North Korean leader Kim Jong-un and Russian President Vladimir Putin signed a new “comprehensive strategic partnership” treaty in Pyongyang on Wednesday, a development that has triggered concerns about heightened geopolitical tensions on the Korean Peninsula.

Under the comprehensive strategic partnership, North Korea and Russia agreed to offer military assistance “without delay” by mobilizing all means possible if either is attacked, according to the full text of the treaty disclosed by the state-run Korean Central News Agency.

After the rare summit where the two leaders “exchanged their pent-up inmost thoughts," Kim declared the North’s relations with Russia have been elevated to “the level of alliance,” while Putin did not go so far as clarifying the new relations as an alliance -- a higher level than a comprehensive strategic partnership.

Despite different tones on the new relationship, Putin’s first visit to Pyongyang in 24 years for the high-profile summit does send loud alarms to South Korea, the United States and other allies regarding the ulterior motives behind the newly signed treaty.

Speculation has mounted that Russia wants North Korea to provide conventional weapons, including the artillery shells it badly needs for its prolonged war in Ukraine. In return, North Korea wants to receive high-end Russian military technology, such as nuclear weapons designs and satellite tech.

South Korean and US officials previously accused North Korea of having sent containers filled with weapons to Russia. Both Pyongyang and Moscow have denied trading arms.

But the possibility remains, as Putin said that Russia does not rule out developing military-technical cooperation with North Korea according to the signed agreement. “Pyongyang has the right to take reasonable measures to strengthen its own defense capability, ensure national security and protect sovereignty,” Putin said.

The Kim-Putin summit came at a time when Russia’s war in Ukraine has been dragging on, the US presidential election approaches and China continues to expand its influence in Asia and beyond.

On Wednesday, the US expressed that growing ties between Pyongyang and Moscow is a trend of “great concern” to those interested in maintaining peace and stability on the Korean Peninsula.

For the US, Russia’s move to step up military cooperation with North Korea looks doubly dangerous. First, the North’s conventional weapons, if provided to Russia, could help Putin shore up his war drive in Ukraine. Second, North Korea’s weapons programs, if advanced through Russia’s help, could pose greater regional and possibly global security risks.

Some experts say that Putin is just using the threat of technology transfer to keep South Korea from offering direct support to Ukraine. There are also doubts about whether Putin will actually help the North expand its nuclear weapons, even though it recently vetoed a UN resolution for a panel of experts monitoring sanctions on North Korea.

China’s role is another factor to watch following the Kim-Putin summit.

A closer military partnership between Russia and North Korea could undermine China’s longstanding position that Pyongyang should continue to work as a buffer zone against the US-allied South Korea. In this regard, China does not want to see its influence over North Korea diminish.

Deepening cooperation between Kim and Putin is an ominous development for the South Korean government, which is trying to deal with intensifying provocations from the North, such as the recent trash-carrying balloon launches and brief crossings of North Korean soldiers into the South.

There are already talks about a return to the confrontations and security risks of the Cold War on the Korean Peninsula. The South Korean government must strengthen multilateral diplomatic efforts to keep the dangerous Pyongyang-Moscow cooperation at bay, working closely with the US and other allies and sending a clear message about red lines to deter the North’s provocations.