South Korea's top diplomat said Wednesday she will talk about preparations for a second summit between Pyongyang and Washington in upcoming talks with US Secretary of State Mike Pompeo in Poland.

"Reviewing the North Korea-US summit preparation process will be the most important agenda item," Foreign Minister Kang Kyung-wha told reporters as she headed to Warsaw.

She plans to meet with Pompeo on Thursday on the sidelines of an international ministerial meeting on peace and security in the Middle East.

The two sides will exchange views on the outcome of a Pyongyang trip by Stephen Biegun, the US special representative for North Korea, last week ahead of the two-day summit between President Donald Trump and the North's leader Kim Jong-un to open in the Vietnamese capital of Hanoi on Feb. 27, according to Kang.

The minister was guarded about another round of working-level talks between the North and the US to take place next week probably in Vietnam.

"I think it's right for the US to announce the schedule," she said. "(Seoul and Washington) are in close consultations."

Regarding Trump's reported remarks on sharing the cost of the US Forces Korea, she made it clear that Seoul has agreed to pay 1.39 trillion won ($927 million) in 2019, up 8.2 percent from a contribution last year.

Speaking at a Cabinet meeting in Washington, DC hours earlier, Trump said, "Working with Secretary (of State) Pompeo and (National Security Adviser) John Bolton, they agreed to pay, yesterday, $500 million more toward their defense ... Five-hundred million, with a couple of phone calls."

Kang wouldn't be drawn into answering a question about Trump's intentions behind his comments.

The two sides struck a one-year contract on defense cost-sharing subject to parliamentary approval in South Korea.

Seoul desired an accord to last three to five years, but Washington demanded a one-year deal.

It means that the allies will have to begin a new round of sensitive bargaining on the money issue not long after the agreement takes effect, probably in spring.

It's uncertain whether Trump was confused about the specific figure in the deal signed over the weekend.

The former businessman might have deliberately inflated the amount of Seoul's share in order to put pressure on it in advance of new negotiations.

He said, "As you know, South Korea -- we defend them and lose a tremendous amount of money ... They've agreed to pay $500 million more. And over the years, it will start going up."

After visiting the Polish capital, Kang is expected to visit the German city of Munich for a three-day security conference to open Friday.

Pompeo will be present at the Munich session as well. (Yonhap)