Japan on Monday put its ballistic missile defences on alert and warned that it would shoot down any projectile that threatened its territory after North Korea notified it of a satellite launch between May 31 and June 11.

Nuclear-armed North Korea says it has completed its first military spy satellite and leader Kim Jong Un has approved final preparations for the launch.

“The government recognises that there is a possibility that the satellite may pass through our country’s territory,” Japan’s chief cabinet secretary, Hirokazu Matsuno, told a regular briefing after North Korea informed the Japanese coast guard of the planned launch.

The order by the Japanese defence ministry, the first in response to a North Korean space launch since 2016, comes after Japan in April dispatched to the East China Sea a destroyer carrying Standard Missile-3 (SM-3) interceptors that can hit targets in space, and sent ground-based PAC-3 missiles, designed to strike warheads closer to the ground, to the Okinawan islands.

Japan expects North Korea to fire the rocket carrying its satellite over the southwest island chain as it did in 2016, a defence ministry spokesperson said.

North Korean state media has criticised plans by its rivals, South Korea, the United States and Japan, to share real-time data on its missile launches, describing the three as discussing “sinister measures” for tightening military cooperation.

Analysts say the satellite is part of a surveillance technology programme, that includes drones, meant to improve its ability to strike targets in the event of war.

Kim in May inspected a military satellite facility, the North’s KCNA state news agency reported.

North Korea has conducted a series of missile launches and weapons tests in recent months, including a new, solid-fuel intercontinental ballistic missile.

Japanese Prime Minister Fumio Kishida told reporters that any North Korean missile launch would be a serious violation of U.N. Security Council resolutions condemning its nuclear and missile activity.

“We strongly urge North Korea to refrain from launching,” his office posted on Twitter, adding it would cooperate with its US ally, South Korea and other countries, and would do all it could to collect and analyse information from any launch.