North Korea is believed to have fired an intercontinental ballistic missile (ICBM) over Japan on Thursday morning.

Residents in the prefectures of Miyagi, Yamagata, and Niigata were warned by Japan’s emergency broadcast system to stay indoors, and trains were halted due to fears that the missile would pass overhead — ultimately, it did not.

According to Yonhap, a South Korean news outlet, North Korea’s ICBM appears to have been a failed launch.

Yasukazu Hamada, Japan’s defense minister, said the ICBM vanished from radar above the Sea of Japan, about 683 miles off Japan’s coast, after reaching an altitude of 1,200 miles and flying 460 miles.

The ICBM launch came one day after North Korea fired more than 20 missiles in a single day, the most yet seen.

One of those missiles flew toward South Korea’s Ulleung Island and landed near the rivals’ tense sea border, activating air raid sirens and forcing its residents to evacuate. South Korea quickly responded by launching missiles along the same border.

Back in 2010, four people were killed after North Korea shelled the front-line South Korean Island of Yeonpyeong, located off the peninsula’s western coast.

Moreover, Thursday’s ICBM was followed by the firing of two short-range missiles an hour later into the Sea of Japan, according to South Korea’s Joint Chiefs of Staff.

The barrage of missiles seen Wednesday came hours after North Korea said that it would use the weapons to make the U.S. and South Korea “pay the most horrible price in history” in reaction to ongoing U.S.-South Korean military drills that Pyongyang sees as practice runs for an invasion, the Associated Press reported.

North Korea’s missile launches on Thursday occurred in the wake of mounting military tensions seen earlier last week. As The Dallas Express reported, South and North Korea exchanged warning shots near disputed western sea borders last Monday.

South Korea’s Joint Chiefs of Staff said in a statement that its navy fired warning shots around 3:40 a.m. local time to repel a North Korean ship that it claims crossed the disputed Northern Limit Line, which was established by the UN at the end of the Korean War.

They condemned the North’s move as a violation of a bilateral military agreement signed in 2018 that prohibits “hostile acts” in border areas and urged it to stop “consistent provocations and accusations,” according to The Dallas Express.

North Korea’s latest missile firings have come at a time when the world’s attention was already focused on South Korea. The country saw its largest disaster in years this weekend when over 150 people were killed during a tragic crowd surge during Halloween celebrations in Seoul, according to The Dallas Express.