SEOUL, South Korea — Japan said Monday that North Korea has informed it of a plan to launch a satellite by June 3, an apparent effort to put its second military spy satellite into orbit.

The launch notification came as leaders of South Korea, Japan and China gathered in Seoul for their first trilateral meeting later Monday.

Japan’s coast guard said it has been notified by North Korea about its planned launch of a “satellite rocket,” with safety cautioning in the waters between the Korean Peninsula and China and east of the Philippine island of Luzon beginning Monday through midnight June 3.

North Korea gives Japan its launch information because Japan’s coast guard coordinates and distributes maritime safety information in East Asia.

The launch plan likely refers to the North’s push to launch its second military spy satellite into space. South Korea’s military said Friday it detected signs that North Korea was engaging in activities believed to be preparations to launch a spy satellite at its main Tongchangri launch facility in the northwest.

Last November, North Korea sent its first military reconnaissance satellite into orbit as part of its efforts to build a space-based surveillance network to deal with what it calls U.S.-led military threats.

North Korean leader Kim Jong Un later told a year-end governing party meeting that the country would launch three additional military spy satellites in 2024.

The U.N. bans North Korea from conducting any satellite launches, viewing them as covers for testing its long-range missile technology.

North Korea has steadfastly maintained it has the right to launch satellites and test missiles in the face of what it calls military threats posed by the United States and South Korea.

The North’s November satellite launch deepened tensions on the Korean Peninsula, with both Koreas taking steps to breach their 2018 agreement to reduce military tensions.

In recent years, North Korea has been engaged in a provocative run of missile tests to modernize and expand its weapons arsenals, prompting the U.S. and South Korea to strengthen their military drills in response.

Experts say North Korea likely believes an enlarged weapons arsenals would increase its leverage in future diplomacy with the U.S.

North Korea wasn’t among matters listed on the official agendas for Monday’s trilateral meeting between South Korean President Yoon Suk Yeol, Japanese Prime Minister Fumio Kishida and Chinese Premier Li Qiang.

But during a bilateral meeting with Li on Sunday, Yoon asked China, as a permanent member of the U.N. Security Council, to contribute to promoting peace on the Korean Peninsula, while speaking about North Korea’s nuclear program and its deepening military ties with Russia, according to Yoon’s office.

South Korea, Japan and the U.S. have long urged China — North Korea’s major ally and economic pipeline — to use its leverage to persuade the North to abandon its nuclear ambitions. But China is suspected of avoiding fully enforcing U.N. sanctions on North Korea and sending clandestine aid shipments to help its impoverished neighbor stay afloat.