The United Nations Security Council plans to have an emergency meeting Tuesday in response to North Korea's latest ballistic missile test.
Uruguay's mission to the U.N. said the meeting was requested by the United States, South Korea and Japan.
North Korea said Monday it is now ready to mass produce intermediate-range ballistic missiles and deploy them to its army.
Seoul's military said the missile was fired Sunday afternoon from South Pyeongan province and flew about 500 kilometers before landing in the Sea of Japan. It was Pyongyang's second missile test in a week and 10th this year.
A joint chiefs statement said, "Our military is closely monitoring signs for additional provocation by the North Korean military and we are keeping a full military readiness."
In response to North Korea's earlier tests, U.S. President Donald Trump dispatched a naval strike group to waters off the Korean peninsula as a warning to the communist regime to end its nuclear weapons development program.
But Secretary of State Rex Tillerson rejected the idea that the U.S. pressure against North Korea is not working.
"We’re early in the stages of applying the economic pressure as well as the diplomatic pressure to the regime in North Korea," Tillerson told Fox News. "Hopefully, they will get the message that the pathway of continuing their nuclear arms program is not a pathway to security, or, certainly, prosperity. The ongoing testing is disappointing, it’s disturbing, and we ask that they cease that because until they cease that testing, clearly, they have not changed their view. But I think we’re early into the game of putting pressure on them."
A @WhiteHouse official says “we are aware that North Korea launched an MRBM.”— Steve Herman (@W7VOA) May 21, 2017
David Benham, spokesman for the U.S. Pacific Command, said the U.S. will "continue to monitor North Korea's actions closely" and "stands behind our ironclad commitment to the security of our allies in the Republic of Korea and Japan."
South Korean President Moon Jae-in held a National Security Council meeting at the presidential Blue House to discuss the missile launch. Japanese Prime Minister Shinzo Abe called the latest test a "challenge to the world."
North Korea has conducted a variety of missile tests since the beginning of last year at an unprecedented pace.
A week ago, Pyongyang launched a missile in an unusual high altitude ballistic path that indicated it might be a new two-stage liquid fueled rocket capable of flying up to 4,500 kilometers.
North Korea said then that it had successfully conducted a newly developed mid-to-long-range missile test, supervised by leader Kim Jong Un and aimed at verifying the capability to carry a "large scale heavy nuclear warhead."
The official news agency KCNA quoted Kim as accusing the United States of "browbeating" countries that "have no nukes," and warning Washington not to misjudge the reality that its mainland is in the North's "sighting range for strike."
That test, according to a White House statement, should “serve as a call for all nations to implement far stronger sanctions against North Korea.”