North Korea fired at least one ballistic missile toward the sea off its east coast on Sunday, a day after South Korea and the US wrapped up their first combined military exercises.

Possibly setting a single-day record for North Korean ballistic launches, the missiles were fired in succession over 35 minutes on Sunday from at least four different locations, including from western and eastern coastal areas and two inland areas north of and near the capital, Pyongyang, South Korea’s joint chiefs of staff said.

The launch also followed a visit to Seoul by the US point man on North Korean affairs, US Special Representative Sung Kim, who departed on Saturday.

He met his South Korean and Japanese counterparts, Kim Gunn and Takehiro Funakoshi, on Friday to prepare for “all contingencies” amid signs North Korea was preparing to conduct a nuclear test for the first time since 2017.

Washington has made very clear directly to Pyongyang that it is open to diplomacy, Kim said during the visit, which wrapped up on Sunday, noting that he was willing to discuss items of interest to Pyongyang, such as sanctions relief.

Last week, the US called for more UN sanctions on North Korea over its ballistic missile launches, but China and Russia vetoed the suggestion, publicly splitting the UN Security Council on North Korea for the first time since it started punishing it in 2006 when North Korea conducted its first nuclear test.

In recent weeks, North Korea has test-fired a range of missiles, including its largest intercontinental ballistic missile (ICBM).