Russian President Vladimir Putin and North Korean leader Kim Jong-un attend a reception in Pyongyang, June 19. Reuters-Yonhap

Speculation is growing that Russia may have provided North Korea with military technology to advance its intercontinental ballistic missile (ICBM) program, given that the latest launch in October was conducted without a new engine test, according to analysts, Monday.

However, they also caution that it may be too early to conclude that Moscow has provided such support. A quid-pro-quo arrangement in exchange for North Korea's troop deployment to support Russia's invasion of Ukraine could involve economic assistance, military support — or a combination of both — they say. But such exchanges would likely remain highly secretive.

According to Rep. Yoo Yong-won of the conservative ruling People Power Party (PPP), Monday, the solid-fuel Hwasong-19 ICBM, which North Korea test-launched on Oct. 31, is presumed to be a new model rather than an upgraded version of an existing missile. Pyongyang has hailed the Hwasong-19 as the "ultimate version" of its ICBMs.

"As indicated by its increased missile body size, diameter and maximum altitude, the Hwasong-19 appears to be a new model rather than a modified version of the solid-fuel Hwasong-18," the Defense Intelligence Agency said in its analysis submitted to Rep. Yoo.

Also, the lawmaker said North Korea is believed to have proceeded with the test-firing of the Hwasong-19 without conducting a new engine test, a process typically required before an advanced ICBM launch.

The military said it has not detected any further signs of solid-fuel engine tests since March 20, when North Korea claimed to have performed a ground test for a solid-fuel engine intended for a new type of intermediate-range hypersonic missile.

These factors add weight to the possibility of Russian technological support.

“It is assessed that North Korea may be receiving technological support from Russia under the pretext of ‘cooperation in the field of space technology,' which could be used for ballistic missile development,” the military stated, according to Rep. Yoo.

However, some analysts who spoke to The Korea Times argued that it is too early to draw such conclusions.

“Without evidence, everything is a question mark. All I can say is that Russia and North Korea are exchanging something in return for Pyongyang's troop deployment in the Ukraine war, but would that be? Money, advanced military technology or less developed technology? The two sides may not have settled on it yet,” said Yang Moo-jin, president of the University of North Korean Studies.

North Korea launches its new Hwasong-19 intercontinental ballistic missile, Oct. 31, in this photo carried by the North's official Korean Central News Agency the next day. Yonhap

Yang noted that the absence of a new engine test before the missile launch does not necessarily indicate Russian involvement, given that North Korea had already made significant progress with solid-fuel missiles prior to the Oct. 31 launch.

"The increased performance of the new missile is fully explainable by the increased size of the Hwasong-19, which is itself fully obtainable from the Hwasong-18 technology base that was probably catalyzed some seven to 10 years ago," said Vann Van Diepen, former principal deputy assistant secretary of the U.S. State Department, in an analysis on 38 North, a website devoted to analysis about North Korea, on Nov. 5.

In that sense, Van Diepen viewed that there was no sign of recent Russian assistance in the latest ICBM launch. However, he added that any future assistance North Korea may receive from Moscow for its ICBM program remains a wild card.

South Korea's Ministry of National Defense said it is analyzing Russia's potential involvement in the Hwasong-19 launch.

"We are currently analyzing the movements of North Korea's missile launches with relevant agencies to make the necessary assessments," ministry spokesperson Jeon Ha-kyu said during a briefing, Monday, in response to a question about the validity of Rep. Yoo's analysis. "We are closely monitoring the overall situation, but there is no specific comment at this point."

North Korean leader Kim Jong-un celebrates the launch of a Hwasong-17 intercontinental ballistic missile (ICBM) from Pyongyang in this photo released by the North's official Korean Central News Agency, March 24. Yonhap

U.S. authorities are also closely following the potential exchange between Moscow and Pyongyang.

"I think Vladimir Putin doesn't know for sure. I think he probably hasn't decided exactly what he's going to do for North Korea on a going-forward basis. But I will tell you this, Kim Jong-un expects that he's going to get something significant, probably in the form of military and technology support from Russia," National Security Adviser Jake Sullivan said in an interview with CBS News, Sunday (local time).

Sullivan added that Russia's support could help North Korea improve its nuclear program.

The latest developments come as North Korea and Russia are set to formalize their military agreement signed by the two leaders in June. This includes a mutual defense provision in the event of an attack on one party.

Russian President Vladimir Putin signed legislation to ratify the bilateral treaty, according to Russian media reports, Saturday. The deal will take effect once both countries have ratified the treaty and exchanged official documents of ratification.