Senior diplomats of Japan, South Korea and the United States agreed Wednesday to boost their security cooperation in reining in the threat posed by North Korea's weapons development program amid growing concerns about the possibility of it conducting a nuclear test.

The commitment was made when Japan's Vice Foreign Minister Takeo Mori held a meeting in Seoul with his South Korean and U.S. counterparts following a flurry of missile tests by North Korea, with the trio urging Pyongyang to cease provocative actions immediately and return to negotiations.

(From L) Japanese Vice Foreign Minister Takeo Mori, South Korean First Vice Foreign Minister Cho Hyun Dong and U.S. Deputy Secretary of State Wendy Sherman pose for photos as they meet for talks in Seoul on June 8, 2022. (Kyodo)

In a joint statement released by Mori, South Korea's First Vice Foreign Minister Cho Hyun Dong and U.S. Deputy Secretary of State Wendy Sherman, they "strongly condemned the repeated unlawful ballistic missile launches" by North Korea while noting that a "path to serious and sustained dialogue remains open."

It also said the three expressed hope that North Korea would "respond positively to international offers of assistance to fight against COVID-19."

The three-way foreign deputy ministerial talks, the first since South Korean President Yoon Suk Yeol took office about a month ago, came as their countries brace for North Korea's first nuclear test since 2017.

"On timing, I don't have anything more. They have obviously done the preparations in Punggye-ri (test site), and my understanding is they could test any time," U.S. special envoy for North Korea Sung Kim said Tuesday in a telephone briefing.

Since last month, the United States has been saying there are signs that North Korea is readying the test site for what could be its seventh nuclear test.

After the Seoul meeting, Sherman reiterated that the three countries are closely aligned on important global and regional issues.

"There is nothing our three countries cannot achieve when we work together," she said at a joint press conference.