The UN secretary-general has strongly condemned North Korea's latest ballistic missile launch ahead of an urgent Security Council meeting, while President Donald Trump pledged to deal with Pyongyang "very strongly".
North Korea has repeatedly flouted six Security Council resolutions demanding an end to its nuclear and ballistic missile activities and has continued to launch missiles, escalating tensions on the Korean peninsula and in the region.
The missile test, conducted early on Sunday, is seen as an implicit challenge to Mr Trump, who has vowed a tough line on North Korea but has yet to release a strategy for dealing with a country whose nuclear ambitions have troubled US leaders for decades.
"North Korea is a big, big problem and we will deal with that very strongly," Mr Trump said at a joint news conference with Canadian prime minister Justin Trudeau on Monday.
UN secretary-general Antonio Guterres called the launch "a further troubling violation of Security Council resolutions" and urged North Korea to comply with its international obligations, UN deputy spokesman Farhan Haq said.
"The secretary-general appeals to the international community to continue to address this situation in a united manner," Mr Haq said.
South Korea condemned what it called "serious military and security threats" and predicted more such tests.
Prime Minister Hwang Kyo-ahn, who is also the acting president, said his country would punish North Korea for the missile launch.
The United States, Japan and South Korea requested the urgent Security Council meeting, which was scheduled to take place behind closed doors later on Monday.
In previous Security Council actions on North Korea, the United States and China, a neighbour and ally of Pyongyang, have been the key negotiators.
After previous ballistic missile tests, the Security Council has issued a strong condemnation, called for redoubled efforts to fully implement sanctions, and reiterated the importance of maintaining peace and stability on the Korean Peninsula and in north-east Asia.
Britain's UN ambassador Matthew Rycroft called the latest test "another flagrant violation" of council resolutions.
"There should be a statement unifying the Security Council and setting out clearly the seriousness of the violation," he said.
North Korea already has a variety of land-based missiles that can hit South Korea and Japan, including US military bases in those countries.
It has also successfully tested a submarine-launched missile and development of such missiles would add a weapon that is harder to detect before launch.
"These are serious military and security threats," Jeong Joon-hee, spokesman at South Korea's Ministry of Unification, told reporters.
"Pyongyang has no intention of backing away from its goal to become a country with nuclear weapons."
North Korea's Central News Agency said the country's leader, Kim Jong Un, was at the launch site to observe Sunday's test and expressed pleasure at the North's expansion of its strategic strike capabilities.
The report early on Monday also said Kim gave the order to fire the "Pukguksong-2", which the agency said was a "Korean style new type strategic weapon system".
It is believed to have flown about 500 kilometres (310 miles) before splashing down into the ocean in international waters.
The report said the test proved "the reliability and security" of a new mobile launching system, the solid fuel that was used, and the guidance and control features of the ballistic missile.
Solid fuel can give missiles a longer range and make detecting them before launch more difficult because they can be readied faster than liquid fuel missiles.
It added that Mr Kim "expressed great satisfaction over the possession of another powerful nuclear attack means".
Reports of the launch came as Mr Trump was hosting Japanese prime minister Shinzo Abe, who called it "absolutely intolerable".
China, facing criticism that it is not doing enough to pressure North Korea to drop its nuclear programme, said on Monday that the root cause of North Korean missile launches is friction with the United States and South Korea.
Foreign Ministry spokesman Geng Shuang said China opposed the launch.