SEOUL: The nuclear-powered aircraft carrier USS Ronald Reagan began a new round of naval exercises with South Korean warships on Friday.

South Korean warplanes conducted the bombing exercise shortly after North Korea fired more ballistic missiles and flew fighter jets.

South Korea deployed 30 warplanes along the border to retaliate. But the conflict was avoided as the North Korean planes withdrew. Missiles fired by North Korea fell between the Korean Peninsula and Japan.

South Korea and the US on Wednesday staged a rare missile drill and deployed warships, including an aircraft carrier, in the Korean Sea in response to North Korea's missile test towards Japan on Tuesday.

North Korea has warned that the US aircraft carrier is a threat to North Korea's security and that there will be severe measures

The drills are aimed at bolstering the allies' defence capabilities and will involve training to escort the Reagan southeast of South Korea's southern island of Jeju, South Korea's Joint Chiefs of Staff said in a statement.

"We will continue to strengthen our firm's operational capabilities and readiness to respond to any provocations by North Korea," the statement said.

North Korea is ready to conduct its first nuclear test in five years and is preparing to test a new liquid-fueled intercontinental ballistic missile and a submarine-launched ballistic missile, Heo Tae-Keun, South Korea's deputy minister of national defence policy, told lawmakers. earlier this week.

US, South Korean and Japanese warplanes have conducted joint weapons drills on the Korean Peninsula. South Korea's military chief says it has stepped up surveillance on North Korea.

The UN Security Council met and assessed the situation.