"The US conducts Continuous Bomber Presence operations as part of a routine, forward deployed capability supporting regional security and our allies in the Indo-Asia-Pacific region," it said.

The operations "are not related to any specific situation or nation."

The statement came as North Korea claimed Tuesday that the bombers flew over the Korean Peninsula less than one day after Seoul and Washington wrapped up their joint military drills at the end of last month.

The allies completed their two-month joint exercises Sunday, with US strategic assets taking part in the training, such as the USS Carl Vinson aircraft carrier, F-35 stealth fighter jets and B-1B bombers.

"The B-1Bs from Guam flew in the sky above the East Sea and took part in coordinated operations with strategic striking units, including the aircraft carrier and a nuclear-powered submarine," the Korean Central News Agency said.

A South Korean military source said that the US bombers joined the military exercises with South Korean fighter jets and planes decked on the Carl Vinson, respectively, as a show of force against North Korea.

"The bombers joined the drills near the Korean Peninsula for about two to three hours," the source added.

This year's military drills came amid heightened tensions on the divided peninsula over another possible North Korean nuclear test and ballistic missile launches.

The US sent a Navy strike group led by the USS Carl Vinson to the region as a show of force amid concerns about the possibility of a pre-emptive strike by Washington against Pyongyang.

North Korea has warned that its military is ready to "sink" the aircraft carrier "with a single strike" if needed.

"Holding a precious sword of nuclear weapons, we are closely watching the military movements of the enemy with full preparations for combat," the KCNA said.

North Korea has claimed that its development of nuclear weapons is a deterrent against what it calls Washington's hostile policy toward it.(Yonhap)