South Korea's Defense Minister Shin Won-sik talks during a press conference held on Monday at the Press Center in Seoul. (Yonhap)

South Korea's Defense Minister Shin Won-sik on Monday reaffirmed that the current size of US troops stationed in the country is "absolutely necessary" after a former top Pentagon official questioned the need for such a presence.

Christopher Miller, who served as the acting secretary of defense under the former Donald Trump administration, said in a recent local media interview that it was time to discuss whether South Korea still needs 28,500 American troops or if change was needed.

"Every year at the Security Consultative Meeting, (we) announce that it is an absolutely necessary figure," Shin said at a news conference when asked about Miller's comments, referring to the annual meeting between the two countries' defense chiefs.

Shin said the current size of the US Forces Korea is outlined annually in the US National Defense Authorization Act, which specifies the Pentagon's budget, and that South Korea shares this view.

Miller's comments came amid concerns of a possible shift in Washington's security policies regarding South Korea if Trump is reelected to office in the November presidential election.

On the upcoming South Korea-US talks on the cost-sharing for the upkeep of US troops stationed here, Shin said he would make efforts to inform Americans on the role South Korea plays in global defense.

"South Korea (bought about) $10 billion worth of American weapons in the past five years," he said. "More importantly, South Korea bears the largest security burden along with the United States to maintain peace and security in the world than any other country."

Earlier this month, Seoul and Washington named their new chief negotiators for the cost-sharing talks, after local media reported they would launch the talks earlier than planned in a move that appeared to consider Trump's possible reelection.

During Trump's presidency, the negotiation was a major bone of contention as he demanded a hefty rise in South Korea's share of the cost for the USFK.

On recently deepening ties between Pyongyang and Moscow, Shin said the North is estimated to have shipped about 7,000 containers of arms and military equipment to Russia since around last July.

The two countries have bolstered relations after the North's leader Kim Jong-un and Russian President Vladimir Putin held a summit at a Russian spaceport in September.

When asked whether Seoul plans to send weapons to support Ukraine, Shin reiterated the government's stance on not providing lethal arms support.

"(We) have never directly provided lethal weapons, equipment or supplies to Ukraine," he said. "As the United States partially lacked shell reserves, we made exports to them ... Unless our government's stance changes, this policy remains in effect."

Seoul has maintained a stance to provide humanitarian and non-lethal defense assistance to Ukraine, such as protective suits, demining equipment and other military supplies. (Yonhap)