The 5 million residents of Hokkaido, Japan’s second largest island, were warned on Tuesday morning local time to take shelter after North Korea launched a missile over the island. After a tense 20 minutes of emergency alerts, the missile was announced to have crashed into the Pacific Ocean.

Residents have reported through social media that all TV channels displayed an urgent message about a possible incoming strike. “The Japanese government is warning a missile could be flying toward Japan,” read a message on NHK World, Japan’s public broadcaster. “Stay indoors, or find shelter. We will bring you more details soon.”

Citizens walking through public spaces reported hearing air raid warnings through PA systems.

The missile is thought by authorities to have launched at 7:22 a.m. local time (3:22 p.m. Monday PT time) and landed in the Pacific 7 minutes later.

North Korea returned to regular missile tests this year, with Tuesday’s incident becoming the fifth test in the past week. The previous four missiles were sent into waters near South Korea and Japan and are thought to be partially in response to Vice President Kamala Harris’ tour of South Korea last week.

North Korea has adopted refreshed aggression against its southern neighbor following the March election of Yoon Suk-yeol as South Korea’s president. When Yoon offered the country economic incentives in exchange for the dismantling of its nuclear program, the Kim regime balked. “It would have been more favorable for his image to shut his mouth, rather than talking nonsense as he had nothing better to say,” Kim Yo Jong, sister of Kim Jong Il, said in a statement released by the country’s state news agency.

After Kim Jong Un in September pledged to never abandon the country’s nuclear program, which has earned the country debilitating sanctions, experts have predicted another North Korean nuclear weapon test is imminent.