North Korean Foreign Minister Ri Yong Ho left Pyongyang on Thursday for an ASEAN-related meeting due to be held later this week in Singapore, Kyodo News confirmed, with the focus on whether he will contact his U.S. and Japanese counterparts while in the city-state.

Ri is expected to make an official visit to Iran after participating in Saturday's ASEAN Regional Forum meeting of the 10-country regional bloc and other forum members, sources with knowledge of his itinerary said.

In Singapore, Ri is likely to try to strengthen relations with his counterparts from countries such as those in the Association of Southeast Asian Nations, as North Korea has recently been working to bolster its economic growth.

With skepticism lingering about whether North Korea will really take concrete steps toward denuclearization, attention is focused on whether Ri will meet with U.S. Secretary of State Mike Pompeo, and to a lesser extent, with Japanese Foreign Minister Taro Kono, on the sidelines of the regional forum.

At his summit with U.S. President Donald Trump in June in the city-state, North Korean leader Kim Jong Un pledged to work toward "complete" denuclearization of the Korean Peninsula.

U.S.-North Korea talks on the specifics of denuclearization, however, are apparently at a standstill.

Meanwhile, Japan's Prime Minister Shinzo Abe has been exploring the possibility of a summit with Kim, but ties between Tokyo and Pyongyang have been worsening over the abduction of Japanese nationals by North Korea in the 1970s and 1980s.

Japan officially lists 17 citizens as abduction victims and suspects North Korea's involvement in many more disappearances.

Abe, placing priority on settling the abduction issue, has expressed a willingness to hold direct talks with North Korea, but Pyongyang has reiterated that the issue has already been resolved.

Pompeo will visit Singapore on Friday after visiting Malaysia, his department said, while Kono arrived in the city-state on Wednesday night. Ri plans to reach Singapore on Friday, flying in from Beijing, the sources said.