South Korea and the United States have deployed the B-52 Stratofortress, a long-range strategic bomber, over the Korean peninsula, Seoul's news agency Yonhap reported Sunday local time. The move comes three days after North Korea said it has tested a hydrogen bomb.

Seoul and Washington said the B-52 bomber left Andersen Air Force Base on Guam Sunday morning and arrived in the skies over Osan, Gyeonggi Province, South Korea, at noon. The bomber flew past Osan surrounded by an entourage of two South Korean F-15Ks and two U.S. F-16s, the militaries told Yonhap. The plane then returned to Guam, Reuters reported.

The flight was "in response to recent provocative action by North Korea," the U.S. military said.

"The United States remains steadfast in its commitment to the defense of the Republic of Korea (South Korea) and to maintaining stability on the Korean peninsula, to include extended deterrence provided by our conventional forces and our nuclear umbrella," said Lt. Gen. Terrence O'Shaughnessy, as quited by Reuters.

The deployment is the second countermeasure employed by the South since North Korea proclaimed its supposed H-bomb test Wednesday. The first was loudspeaker broadcasts condemning the North, which were resumed along the inter-Korean border about four months after they'd been stopped.

The long-range bomber is capable of delivering nuclear weapons, the Associated Press noted. That factor could further enrage Pyongyang, which justifies its pursuit of atomic weapons on what it sees as past nuclear-backed moves by the United States to topple its government.

After North Korea's third nuclear test in 2013, the U.S. also sent its most powerful warplanes to drills with South Korea.

Earlier Sunday, North Korea's Korean Central News Agency quoted leader Kim Jong Un as saying no one had the right to criticize its nuclear tests, Reuters reported.

"The DPRK's H-bomb test ... is a self-defensive step for reliably defending the peace on the Korean peninsula and the regional security from the danger of nuclear war caused by the U.S.-led imperialists," KCNA quoted Kim as saying.

The North's official name is the Democratic People's Republic of Korea.

"It is the legitimate right of a sovereign state and a fair action that nobody can criticize," he said.