SEOUL, South Korea — A ballistic missile fired from a North Korean submarine on Wednesday flew about 310 miles, the longest distance achieved by the North for such a weapon, Seoul officials said, putting all of South Korea, and possibly parts of Japan, within its striking distance.
North Korea already has a variety of land-based missiles that can hit South Korea and Japan, including US military bases in those countries. But its development of reliable submarine-launched missiles would add weapons that are harder to detect before liftoff.
South Korea’s military condemned the launch as an ‘‘armed protest’’ by North Korea against the start of annual South Korean-US military drills, but acknowledged it was an improvement over previous tests of similar missiles.
‘‘North Korea’s nuclear and missile threats are not imaginary threats any longer, but they’re now becoming real threats,’’ South Korean President Park Geun-hye said of the launch. ‘‘Those threats are coming closer each moment.’’
The United Nations Security Council scheduled an emergency meeting on the launch at the request of the United States and Japan. The United Nations said the council would hold closed consultations on the launch late Wednesday afternoon.
State Department spokeswoman Elizabeth Trudeau said in a statement that the United States strongly condemned the launch and called on North Korea to ‘‘refrain from actions and rhetoric that further raise tensions in the region.’’ She said the missile launch marked the latest in an ‘‘accelerating campaign’’ of missile tests that violate multiple UN Security Council resolutions.
‘‘The US commitment to the defense of our allies including the Republic of Korea and Japan in the face of these threats remains ironclad,’’ she said.
The missile, fired from a submarine off the eastern North Korean coastal town of Sinpo, reached into Japan’s air defense identification zone, according to Seoul and Tokyo officials. The US Strategic Command said it tracked the launch of the presumed KN-11 missile into the Sea of Japan.
Its 310-mile flight puts all of South Korea within its range if it is fired near the two countries’ border.
Missiles of such capability could also potentially strike parts of Japan, including US military bases on the island of Okinawa, considering the operational range of North Korea’s Sinpo-class submarines, which can move about 620 miles underwater at a time, said analyst Kim Dong-yub at Seoul’s Institute for Far Eastern Studies.
North Korea fired two missiles from submarines earlier this year, but South Korean defense officials believe they exploded in midair after flying less than 18 miles.
The launch was the latest in a series of missile, rocket, and other weapon tests this year by North Korea, which is pushing to acquire reliable weapons that are capable of striking targets as far away as the continental United States.
In June, North Korea, after a string of failures, sent a midrange ballistic missile more than 870 miles high. Analysts say the flight showed North Korea has made progress in its push to be able to strike US forces throughout the region.
Many outside experts say North Korea doesn’t yet have a functioning long-range nuclear missile capable of reaching the continental United States, but they acknowledge that the North has been making steady progress in its weapons programs and could one day develop such a weapon. Some civilian experts have said they believe the North already has the technology to put warheads on shorter-range missiles that could strike South Korea and Japan.
Japanese Prime Minister Shinzo Abe called the launch an ‘‘impermissible and outrageous act’’ that poses a grave threat to Japan.