South Korean President Lee Jae Myung announced the finalisation of a long-awaited security and trade agreement with the United States last week, including plans to move forward with developing atomic-powered vessels.

Seoul said it had secured "support for expanding our authority over uranium enrichment and spent-fuel reprocessing".

In its first comments responding to the deal, the nuclear-armed North fired back that the submarine programme was a "dangerous attempt at confrontation".

The agreement is a "serious development that destabilises the military security situation in the Asia-Pacific region beyond the Korean peninsula and causes the situation of impossible nuclear control in the global sphere," said the commentary carried by the official Korean Central News Agency (KCNA) on Tuesday.

South Korea's possession of nuclear submarines "is bound to cause a 'nuclear domino phenomenon' in the region and spark a hot arms race," Pyongyang added.

The commentary comes just a day after Seoul proposed military talks with Pyongyang to prevent border clashes, the first such offer in seven years.

President Lee has also offered to hold broader discussions with the North without preconditions, a sharp reversal from the hawkish stance taken by his conservative predecessor.

North Korea has yet to respond to Lee's overtures.