North Korea staged its sixth and largest nuclear test on Sunday following a series of missile launches, including nine since the new South Korean leader took office in May.

The Japanese premier noted the two countries are working closely together to fend off the North's threats. Moon and Abe held three telephone conversations in July alone.

"I am glad to see that we are forming a close relationship, under which we have been able to hold detailed and timely discussions on many challenges so far," Abe said through his interpreter.

"I believe North Korea's repeated provocations pose a very dangerous threat that has not been witnessed before. We have successfully worked closely together until now, but I hope we will continue to work closely together to deal with the issue," he added.

Moon also vowed enhanced cooperation between the two countries.

"We spared most of the time in our telephone conversations to the North Korean nuclear issue. We cannot but have to closely discuss the issue again today, but in addition to that, I wish we can begin discussing issues related to economic cooperation," the South Korean president said.

Abe agreed on the need to further expand the countries' bilateral relationship.

"I wish to establish new, future-oriented ties in various areas," he said. (Yonhap)