In Sri Lanka, the top diplomat will hold talks with Foreign Minister Mangala Samaraweera and pay courtesy calls on the president and the foreign minister there. In Vietnam, he will meet with Foreign Minister Pham Binh Minh and pay a courtesy visit to Prime Minister Nguyen Xuan Phuc.

The two trips will focus on deepening South Korea's economic cooperation with the Asian countries as well as stepping up their collaboration over North Korea's provocations, according to the foreign ministry here.

Last week, North Korea fired four ballistic missiles, the latest military provocation which followed the country's test of a new type of intermediate ballistic missile last month.

A month earlier, North Korean leader Kim Jong-un's half brother Kim Jong-nam was assassinated by North Korean suspects at Kuala Lumpur International Airport, resulting in severe diplomatic tension with Malaysia.

"Yun's visit to Sri Lanka and Vietnam is expected to produce a milestone in strengthening collaboration with the Southeast and Southwest Asian region in dealing with North Korea," the ministry said.

En route to Sri Lanka on Tuesday, the minister plans to briefly stop in Singapore for talks with the city state's Foreign Minister Vivian Balakrishnan, focusing on security and global issues, the ministry also noted. (Yonhap)