They were joined by warplanes from the USS Carl Vinson aircraft carrier operating in the East Sea for the "frantic" drill, according to the Korean Central News Agency.

A government source in Seoul confirmed that two B-1Bs arrived in the airspace over the East Sea at around 10:30 a.m., five hours after the North test-fired a short-range ballistic missile.

The bombers were accompanied by South Korea's F-15K fighter jets during the two-hour unannounced flight near and over the peninsula, the source said.

It was apparently a show of force against Pyongyang for its continued provocations.

Nicknamed "The Bone," the B-1B Lancer is a long-range, multi-mission bomber capable of flying intercontinental missions without refueling. The supersonic aircraft can reach Korea in 2 1/2 hours from a US Air Force base in Guam.

The North has responded sensitively to the deployment of the US military's strategic assets in the vicinity of the peninsula.

"Such military provocations of the US imperialists is a dangerous reckless racket for bringing the situation on the Korean peninsula to the brink of a war," it said in the English-language report.

The military action "clearly proves that their talk about 'dialogue' is nothing but hypocrisy to disarm the DPRK and their wild ambition to eliminate the DPRK with nukes remains unchanged even a bit," the KCNA argued, using the acronym of the North's official name.

It reiterated the North Korean military's strongly worded war threat.

"The US imperialist warmongers should not forget even a moment that their increasing danger of a nuclear war on the Korean peninsula would precipitate a disaster which the US mainland turns into a scorched-earth," it said. (Yonhap)