South Korean and US forces have launched large-scale joint naval drills in a show of force against what they call North Korea’s provocations in the restive region.

The six-day maneuver, dubbed Invincible Spirit 2016, is held in the waters round the Korean Peninsula, announced South Korea’s Defense Ministry on Monday.

South Korean Defense Ministry spokesman Moon Sang-gyun said the maneuver “aims at showing the allied forces’ strong commitment to countering a series of North Korean provocations such as a nuclear test and improve their maritime interoperability.”

The US has deployed nuclear-powered aircraft carrier “USS Ronald Reagan” along with seven warships, while South Korea has mobilized about 40 warships.

According to media reports, the drills could feature for the first time rehearsals of targeting North Korean leaders and atomic sites in the event of a nuclear strike by Pyongyang.

Such drills anger Pyongyang, which says the exercises are a rehearsal for a full-scale invasion of the North.

On September 26, Seoul and Washington carried out wargames in the Sea of Japan, less than a week after two US nuclear-capable bombers flew over the Korean Peninsula.

A US Navy crew member looks at an F/A-18 Super Hornet fighter landing onto the deck of the USS Ronald Reagan during joint naval drills between South Korea and the US in the West Sea, October 28, 2015. (Photo by AP)

Tensions between two Koreas have been simmering in the past year since Pyongyang conducted a new series of missile and nuclear tests. The North has been under strict UN sanctions for such tests since 2006.

Pyongyang has pledged to develop a nuclear arsenal to protect itself from the US military, which occasionally deploys nuclear-powered warships and aircraft capable of carrying atomic weapons in the Asia-Pacific region.

Last month, North Korea conducted its fifth and biggest ever nuclear test, saying it was meant to counter US hostility.

In January, Pyongyang said it had successfully detonated a hydrogen bomb and vowed to build up its nuclear program as deterrence against potential aggression from the US and its regional allies.

A month later, Pyongyang launched a long-range rocket, which it said placed an earth observation satellite into orbit. Washington and Seoul denounced it as a cover for an intercontinental ballistic missile test.

North Korea says it will not give up on its nuclear deterrence unless Washington ends its hostile policy toward Pyongyang and dissolves the US-led command in South Korea. Thousands of US soldiers are stationed in South Korea and Japan.