File photo of Ballistic rocket is seen launching during a drill by the Hwasong artillery units of the KPA Strategic Force in this undated picture provided by KCNA in Pyongyang on July 21, 2016.

Monday's launch was Pyongyang's 9th test of 2017, adding to the dozens of short and long-range tests it has conducted since the start of last year, in defiance of U.N. Security Council resolutions. North Korea last test-fired a ballistic missile on May 21 off its east coast.

The missile was believed to be a Scud-class ballistic missile and flew about 450 km (280 miles), the Joint Chiefs said in a statement. North Korea has a large stockpile of Scud missiles, originally developed by the Soviet Union.

The launch was immediately reported to South Korean President Moon Jae-in, who called a meeting of the National Security Council, South Korea's Office of the Joint Chiefs of Staff said in a statement. Moon has advocated engaging the North Koreans in dialogue, which would be a reversal of South Korea's existing policy.

North Korea fired what appeared to be a short-range ballistic missile on Monday, its 9th test of the year and a new challenge to worldwide efforts to resolve the Peninsula's crisis diplomatically.

The move poses a challenge to the posture of the United States, which in recent weeks has warned that its "strategic patience" with North Korea was nearing an end.

President Donald Trump, who was briefed on the launch upon his return to the White House, chided North Korea's launch as a 'great disrespect' to China, Pyongyang's biggest ally. The two countries share an 870-mile border, and trade between North Korea and China has surged by nearly 38 percent in the last year—even as the crisis has gathered momentum.

North Korea has shown great disrespect for their neighbor, China, by shooting off yet another ballistic missile...but China is trying hard!

On Sunday, North Korean leader Kim Jong Un reportedly supervised test runs of new anti-aircraft weapons, amid heightened tensions on the Korean Peninsula. Experts say the North appears to be gaining meaningful data that is fed into its effort to build an intercontinental ballistic missile.

Meanwhile, neighboring Japan lodged a protest against the North's latest missile launch, which appeared to have landed in Japan's exclusive economic zone, Chief Cabinet Secretary Yoshihide Suga said.

"This ballistic missile launch by North Korea is highly problematic from the perspective of the safety of shipping and air traffic and is a clear violation of United Nations Security Council resolutions," Suga told reporters in televised remarks.

Japanese Prime Minister Shinzo Abe vowed action along with other nations to deter Pyongyang's repeated provocations.

As we agreed at the recent G7, the issue of North Korea is a top priority for the international community," Abe told reporters in brief televised remarks. "Working with the United States, we will take specific action to deter North Korea."

In an interview on Sunday with CBS's "Face the Nation," Defense Secretary James Mattis cautioned that a conflict with the hermetic Communist nation "would be probably the worst kind of fighting in most people's lifetimes," and could be "catastrophic" if not resolved diplomatically.

A report in the Voice of America cited unnamed sources as saying the U.S. was ordering a third aircraft carrier strike force to the region, as a warning to Kim to stand down. The USS Carl Vinson and the USS Ronald Reagan are already stationed in the Pacific Ocean.

--NBC News contributed to this article.