ⓒYONHAP NewsNorth Korea fired an intermediate-range ballistic missile, or IRBM, on Tuesday in its longest-ever weapons test. As the projectile flew over Japan, residents in northern areas of the island country were instructed to stay indoors as an alert was transmitted through a nationwide system. South Korea and the U.S. in response carried out precision-strike drills, mobilizing tactical missiles and fighter jets. After massive combined drills last month with South Korea and Japan near the Korean Peninsula, the nuclear-powered USS Ronald Reagan has also returned to the East Sea.

Report: North Korea fired a intermediate-range ballistic missile from the northern province of Chagang Tuesday morning, sending the projectile on a trajectory over northern Japan.

[J-alert siren playing out in northern Japan]

The Japanese government was forced to issue an alert urging residents in the northernmost island of Hokkaido and the northeastern prefecture of Aomori to stay inside buildings and take shelter from any potential falling debris.

The South Korean Joint Chiefs of Staff said the North Korean missile landed thousands of kilometers outside Japan's Exclusive Economic Zone about 21 minutes later.

[Joint Chiefs of Staff Spokesman Col. Kim Joon-rak (Korean-English)] 

“The South Korean military this morning detected an intermediate-range ballistic missile which North Korea fired from Mupyong-ri in Chagang Province. Fired eastward, the missile flew over the sky of Japan. Its flight distance was four-thousand-500 kilometers, reaching an altitude of 970 kilometers at the speed of Mach 17." 

The launch on Tuesday marked North Korea's longest-ever weapons test to date. Flying a total of four-thousand-500 kilometers, the test also made it clear that North Korean weapons can reach the U.S. territory of Guam, just about three-thousand-400 kilometers away from Pyongyang. 

Military analysts said the projectile could have been a Hwasong-12 mid-range ballistic missile, which Pyongyang has previously claimed can carry a heavy nuclear warhead.

Calling the missile launch a "reckless nuclear provocation," South Korean President Yoon Suk Yeol told reporters that North Korea will be met with a decisive response by the South Korean military and its allies as well as the international community.

[S. Korean & US militaries firing surface-to-surface missiles (Oct. 5/location undisclosed)]

The allied forces of South Korea and the U.S. in response fired four ATACMS(Army Tactical Missile Systems) guided missiles early morning Wednesday and released video footage of the tactical ballistic missile drill.

Four South Korean F-15Ks and four U.S. F-16 fighters also carried out a precision-strike exercise earlier on Tuesday, dropping two Joint Direct Attack Munition, or JDAM, guided bombs on targets in the Yellow Sea. 

After participating in massive combined drills last week with South Korean and Japanese warships near the Korean Peninsula, the nuclear-powered USS Ronald Reagan supercarrier was also rerouted to return to the East Sea, according to the South Korean military. 

The latest move comes amid signs suggesting that North Korea might conduct its seventh underground nuclear test and concerns of an intercontinental ballistic missile test.

The last time North Korea fired a missile over the Japanese archipelago was in September of 2017, shortly after the “fire and fury” war of words between then-U.S. President Donald Trump and North Korean leader Kim Jong-un.

As of Saturday, North Korea has carried out 10 separate missile tests since the Yoon Suk-yeol administration took office in May. With the latest launch of two short-range missiles on Thursday morning, there have been a total of six launches in the last two weeks with 10 missiles fired.