SEOUL, South Korea — North Korea launched multiple close-range ballistic missiles toward the sea on Tuesday, South Korea’s military said, the latest in a series of weapons demonstrations by North Korea this year.

South Korea’s Joint Chiefs of Staff said the missiles were fired from Jongju city on the North’s west coast.

It said South Korea’s military has bolstered surveillance posture and is closely exchanging related information with the U.S. and Japan.

It was North Korea’s first weapons launch event since April 19, when the country fired multiple short-range missiles in what state-media described as a demonstration of cluster bomb warheads.

North Korean leader Kim Jong Un has focused on expanding his nuclear and missile arsenals since his nuclear diplomacy with U.S. President Donald Trump collapsed in 2019. Trump has repeatedly expressed his desire to resume talks with Kim, but Pyongyang has so far ignored the overtures and urged Washington to drop demands for the North’s nuclear disarmament as a precondition for talks.

Kim has taken an increasingly hardline stance toward South Korea, calling it his country’s permanent and most hostile enemy and taking steps to terminate all ties.

Earlier Tuesday, South Korean President Lee Jae Myung during a Cabinet meeting called for stronger efforts to advance the country’s military. He emphasized artificial intelligence and drone capabilities and the potential acquisition of a nuclear-powered submarine, an issue that has been part of his diplomacy with Washington.

Lee, a liberal who espouses improved ties with North Korea, did not specifically comment on the threats posed by the North. But he stressed the importance of South Korea demonstrating the “resolve to take responsibility for and protect our own security ourselves,” saying such a posture would also strengthen the country’s alliance with the United States.