Last week, a US official warned that North Korea appeared to be preparing for an intercontinental ballistic missile test during Biden’s trip, after satellite imagery revealed activity at a launch site near the capital, Pyongyang.

To date, Biden’s strategy has yet to yield a working meeting with North Korea in the year since the administration completed a review of the US policy toward the hermit kingdom, a senior administration official said, adding that “it has not been for lack of trying.”

Meanwhile, Yoon said that South Korea and its allies stand ready for any acts of North Korean provocation.

The latest launches mark the 16th time that North Korea has tested its missiles this year, including what the US believes was a failed intercontinental ballistic missile test on May 4 that exploded shortly after launch.

US military and intelligence agencies assess Pyongyang may also be preparing for its first underground nuclear test in nearly five years.

The office of Japan’s Prime Minister also announced that a possible ballistic missile had been launched from North Korea on Wednesday, with the Japanese Coast Guard issuing a warning to vessels at 6:03 a.m. local time (5:03 p.m. ET Tuesday.)

“The Ministry of Defense has reported that a possible ballistic missile has been launched from North Korea,” it said, adding: “We advise vessels to keep an eye out for further information, and if you see any falling objects, do not approach them and report all relevant information to Japan’s Coast Guard.”