North Korea has threatened to act against the US military's deployment of a strategic bomber in South Korea, saying US strategic assets are "the first targets of destruction."

A nuclear-capable B-52 bomber took part in a joint drill with the South Korean air force and landed at a South Korean air base in the country on Tuesday.

A commentary on Friday by the state-run Korean Central News Agency said, "This is the intentional nuclear war provocative moves of the US driven into a tight corner at home and abroad."

It said, "The period when the right to preemptive attack was the 'monopoly' of the US has already come to an end."

The commentary added, "The US would be well aware that the Korean peninsula is in a state of war by law and its strategic assets deploying in the puppet region are the first targets of destruction."

North Korea recently objected to a port call by a US nuclear-powered aircraft carrier at a South Korean port. Pyongyang denounced the port call in a commentary in state-run media. It indicated that US bases in Japan are also potential targets, as the aircraft carrier is based in Yokosuka, near Tokyo.