South Korea's Foreign Minister Kang Kyung-wha says North Korea must make concrete pledges regarding its denuclearization in the second summit with the U.S. next month. 

The top diplomat, who is attending the World Economic Forum in Davos, Switzerland, made the remarks on Thursday in an interview with Reuters.

Kang said that the North should make concrete denuclearization pledges, such as dismantling its Yongbyon nuclear facility and allowing international inspections to confirm the process, when leader Kim Jong-un meets U.S. President Donald Trump next month. 

The minister said she is optimistic that North Korea will agree to concrete steps toward abandoning its nuclear weapons and ballistic missile programs.

Kang said Pyongyang and Washington have made “broad agreement” on the timing of their second summit and that a date could be announced “very soon."