Seoul: North Korea on Wednesday test-fired a submarine-launched ballistic missile (SLBM) in waters off its east coast, the South Korean military said.

The launch near the port city of Sinpo around 5.30 a.m. (local time) was in an apparent show of defiance against the ongoing military drill between Seoul and Washington, Yonhap news agency quoted Joint Chiefs of Staff (JCS) as saying.

The military said the missile flew about 500 km, which is an improvement compared with past launches. It fell into waters inside Japan’s air defence identification zone.

Tensions are high on the divided peninsula as North Korea threatened on Monday to wage a “pre-emptive nuclear strike” on South Korea and the US against the allies’ annual military exercise.

Meanwhile the US military confirmed that North Korea has test-fired a submarine-launched ballistic missile, condemning the hermit state’s latest provocation and vowing to raise concerns at the United Nations.

US Strategic Command said the launch of what was believed to be a KN-11 missile off the coast of Sinpo, North Korea, did not pose a threat to North America, citing analysis by the North American Aerospace Defense Command.

The missile, launched at 2029 GMT Tuesday (4:59 am Wednesday local time), fell into the Sea of Japan some 300 miles (480 kilometers) off the coast of North Korea.

“Our commitment to the defense of our allies, including the Republic of Korea and Japan, in the face of these threats, is ironclad, said Commander Gary Ross, a Pentagon spokesman. We remain prepared to defend ourselves and our allies from any attack or provocation.

We call on North Korea to refrain from actions that further raise tensions in the region and focus instead on taking concrete steps toward fulfilling its commitments and international obligations. Several UN Security Council resolutions demand that Pyongyang suspend all of its ballistic missile program activities.

Japanese Prime Minister Shinzo Abe condemned a ballistic missile launch by North Korea as a reckless act, Jiji Press reported. It is a grave threat to Japan’s security environment, Abe told reporters today, according to the news agency. It is an unforgivable, reckless act.

AFP