SEOUL: North Korea fired two short-range ballistic missiles (SRBMs) off its east coast on Friday, South Korea's military said, while South Korean forces were wrapping up nearly two weeks of exercises aimed at deterring their northern neighbour.

The missile launches, at a time of growing fears that North Korea is preparing its first nuclear test since 2017, were the latest in a year in which North Korea has tested a record number of missiles, whether short-range missiles, intercontinental ballistic missiles (ICBMs), or others.

The SRBMs were fired from the Tongcheon area in the North's Gangwon province, the South's Joint Chiefs of Staff (JCS) said, four days after the neighbours exchanged warning shots off the west coast of the divided peninsula.

"Our military is maintaining full readiness posture," the JCS said in a statement, adding that it had stepped up monitoring and security while co-ordinating closely with the United States.

The launches did not pose an immediate threat to the United States or its allies, the U.S. military's Indo-Pacific Command said in a statement.

However they "highlight the destabilising impact" of North Korea's unlawful weapons of mass destruction and ballistic missile programmes, it added.

The nuclear envoys of South Korea, the United States and Japan spoke by telephone and condemned the launches as a provocation and violation of U.N. Security Council resolutions, South Korea's foreign ministry said.

"North Korea's nuclear and missile development will only lead to strengthening security cooperation in the region and abroad," the ministry said in a statement, urging North Korea to return to talks.

South Korean troops were set on Friday to finish the 12-day Hoguk 22 field exercises, which have included some drills with U.S. troops.

About 240 South Korean and U.S. warplanes are due to begin the Vigilant Storm drills on Monday, flying 1,600 sorties in the largest number of missions ever staged for such exercises, the U.S. Air Force said. Read full story

'INCREDIBLY CONCERNING'

The allied aircraft will perform "major air missions such as close air support, defensive counter air, and emergency air operations 24 hours a day during the training period," the air force said.

Ground forces will also practice base defence procedures and survivability in case of attack.

North Korea has said its recent missile launches were in protest against the joint exercises, which it says are provocative and a rehearsal for an invasion.

South Korea and the United States say the exercises are defensive and needed to counter the North's threats.

The United States and its allies believe the North could be about to resume nuclear bomb testing for the first time since 2017.

South Korean President Yoon Suk-yeol has said the North has completed all the technical preparations needed for an underground blast at its Punggye-ri test site, which has been officially shuttered since 2018.

North Korea held six nuclear tests there from 2006 to 2017.

A seventh North Korean nuclear test would be further "confirmation of a programme which is moving full steam ahead in a way that is incredibly concerning," the head of the U.N. nuclear watchdog said on Thursday. 

South Korea has warned that a resumption of the North's nuclear testing would have to be met with an "unparalleled" response from the allies, but neither it nor the United States has given details.