A US naval strike group led by the aircraft carrier USS Nimitz will arrive in South Korea this weekend for sea drills, officials said Friday, following joint exercises that infuriated North Korea.

As well as the nuclear-powered Nimitz, the group includes three guided-missile cruisers and destroyers, the US military said in a statement, without specifying the total size of the group.

A port call in the southern city of Busan is planned for Saturday.

"US Navy ship visits are a tangible symbol of US commitment in the region and show continued interest in ensuring a climate for regional stability and economic prosperity," the statement said.

Military tensions on the Korean peninsula have been high for months, with the North issuing a series of apocalyptic threats over what it sees as intensely provocative US-South Korean joint exercises.

The friction has smoothed in the past week after the annual ground exercises were wrapped up at the end of April, and a US defence official said North Korea had moved two medium-range missiles off their launch pads.

The 97,000-ton Nimitz, one of the world's largest warships, will participate in joint search-and-rescue operations as well as "sea manoeuvring" around the Korean Peninsula, the South's defence ministry said.

The ministry declined to confirm news reports that the drills would be staged next week along the southern and eastern coasts following an ongoing anti-submarine exercise in the Yellow Sea.

North Korean troops near the disputed Yellow Sea border have been ordered to strike back if "even a single shell drops" in their territorial waters, the North's army command said in a statement on Tuesday.

Any subsequent counterstrike would trigger an escalated military reaction that would see South Korea's border islands engulfed in a "sea of flames", it said.

North Korea shelled one of the islands, Yeonpyeong, in November 2010, killing four South Koreans and sparking brief fears of a full-scale conflict.