The series of tests is among the most missiles ever launched by North Korea in a month, analysts said, as it begins 2022 with a dizzying display of new and operational weapons.
South Korea's Joint Chiefs of Staff said it had detected the launch of what it presumed were two ballistic missiles at about 8 a.m. (2300 GMT) from near Hamhung, on the east coast of North Korea. They travelled for about 190 km to an altitude of 20 km, JCS added.
North Korea said this month it would bolster its defences against the United States and consider resuming "all temporally-suspended activities", an apparent reference to a self-imposed moratorium on tests of nuclear weapons and long-range missiles.
The launch came after North Korea fired two cruise missiles into the sea off its east coast on Tuesday, adding to the tension over its tests.
Earlier in the month, North Korea tested tactical guided missiles, two "hypersonic missiles" capable of high speed and manoeuvring after lift-off, and a railway-borne missile system.
In a speech to the U.N.-sponsored Conference on Disarmament on Tuesday, North Korea's Ambassador to the United Nations in Geneva, Han Tae Song, accused the United States of staging hundreds of "joint war drills" while shipping high-tech offensive military equipment into South Korea and nuclear strategic weapons into the region.
"(This) is seriously threatening the security of our state," Han said.
