US forces have unveiled a nuclear-capable B-52 strategic bomber deployed at a South Korea air base, in an apparent show of force against North Korea.

The B-52 was put on full display for a group of reporters in the central city of Cheongju on Thursday, in the strategic bomber's first known arrival at a South Korean air base.

On Tuesday, the B-52 made a flyover at a defense equipment exhibition near Seoul. Later in the day, the bomber took part in a joint drill with the Korean air force.

On Thursday, General Kim Seung-kyum, Chairman of South Korea's Joint Chiefs of Staff, visited the air base along with other US and South Korean officials.

General Kim warned, "If the enemy uses nuclear weapons, the North Korean regime will face its end."

The South Korean military said the deployment of the B-52 is part of efforts to bolster the US' extended deterrence commitment to mobilize the full range of its military capabilities, including nuclear, to defend its ally.

Several South Korean media organizations quoted a South Korean military official as saying that the B-52 is expected to conduct joint drills on Sunday with the country's air force and Japan's Air Self-Defense Force.