A fire burns in an apartment building that was hit during a Russian drone strike, amid Russia's attack on Ukraine, in Kyiv, Ukraine. (Reuters-Yonhap)

South Korea on Wednesday acknowledged the need to send a "monitoring team" to the Ukraine battlefield, but it denied allegations that it was considering supplying 155 mm artillery shells upon Ukraine's request.

"We are obliged to look into, analyze and monitor North Korean armed forces' activities (in the Russia-Ukraine war) while taking a defensive posture," an official of the presidential office said on condition of anonymity Wednesday. "We feel the need to create and dispatch (to Ukraine), whatever we call it -- war situation analysis team or monitoring team -- in advance."

Earlier Tuesday, President Yoon Suk Yeol told Ukraine President Volodymyr Zelenskyy in a phone conversation that North Korean armed forces gaining experience in modern warfare in Ukraine poses a serious security threat, as it would be the first time that North Korean troops have engaged in active combat since the 1950-53 Korean War.

Yoon's office also confirmed that South Korea will start discussions with Ukrainian counterparts this week over plans for a Ukrainian delegation to visit South Korea.

The official, however, denied accusations from opposition party lawmakers on Wednesday that Ukraine had asked for 155 mm artillery shells from South Korea.

"As we further discuss plans for arms support to Ukraine, defensive weapons will be the priority option," said the official, who declined to be named.

This has come as South Korea remains watchful of possible North Korean troop deployments to Ukraine in the near future, amid speculations that some of the soldiers might have already arrived at the combat zone.

South Korea's Defense Intelligence Agency on Wednesday signaled that there is a "likelihood" that North Korean armed forces might have arrived at the front line of the Ukraine war, just over a week after media revelations of North Korean soldiers' presence in eastern Russia.

Rep. Lee Seong-kweun of the ruling People Power Party, who attended the National Assembly's parliamentary audit of the nation's military intelligence authorities on Wednesday, told reporters that the DIA reported to him that North Korean vanguards and some weapons "may be present" at the war front, but this does not indicate North Korea's intervention in the war.

An official from President Yoon's office said they "would not confirm any further" than what was revealed at the parliamentary audit, with respect to suspicions of the North Korean vanguard in Ukraine.

As of Wednesday, South Korea's presidential office estimated that at least 3,000 troops are near the combat zone in western Russia, potentially in "numerous locations" in Russian regions, including Russia's Kursk region and Russian-occupied Donetsk, adding that it was watchful of the possible North Korean intervention in the war.

Ukraine's President Zelenskyy has shared a Ukrainian intelligence assessment that the North Korean troops would start to enter battlefields in Ukraine on Sunday.

Meanwhile on Wednesday, Yoon in a phone call with Canadian Prime Minister Justin Trudeau said that North Korea's troop deployment to the Ukraine front could occur in the near future, reiterating what he told European Commission President Ursula von der Leyen two days earlier.

According to Yoon's office, the president explained to Trudeau that the movement of North Korean soldiers to the Ukraine front lines "could be at a swifter pace than anticipated."

During his talks with Trudeau, Yoon expressed hope that the upcoming inaugural foreign and defense ministers' meeting between South Korea and Canada could "institutionalize high-level talks over security issues" and "deepen mutually beneficial defense industry cooperation."

According to Yoon's office, South Korea is one of the countries, along with France, Germany, Spain and Sweden, which has shown appetite to bid for Canada's upcoming project to make up to 12 naval submarines, each 3,000 tons, which South Korea has estimated could be valued at some 20 trillion won ($14.5 billion).

On Friday, South Korea's Foreign Minister Cho Tae-yul and Defense Minister Kim Yong-hyun are set to meet with Canadian Minister of Foreign Affairs Melanie Joly and Minister of National Defense Bill Blair.