SEOUL (REUTERS) - The United States deployed a B-52 bomber on a low-level flight over its ally South Korea yesterday, in a show of force following North Korea's nuclear test last week.
North Korean leader Kim Jong Un maintained that last Wednesday's test was of a hydrogen bomb and said it was a self-defensive step against a US threat of nuclear war.
North Korea's fourth nuclear test angered both China, its main ally, and the US, although the American government and weapon experts doubt the North's claim that the device was a hydrogen bomb.
The massive B-52, based in Guam and capable of carrying nuclear weapons, could be seen in a low flight over Osan Air Base at around noon. It was flanked by two fighter planes, a US F-16 and a South Korean F-15, before returning to Guam, the US military said in a statement.
Osan is located south of Seoul and 77km from the Demilitarised Zone, which separates the two Koreas.
The flight was "in response to recent provocative action by North Korea", the US military said.
"The United States remains steadfast in its commitment to the defence of (South Korea) and to maintaining stability on the Korean peninsula, to include extended deterrence provided by our conventional forces and our nuclear umbrella," said US Lieutenant-General Terrence O'Shaughnessy.
After the North's last test, in 2013, the US sent a pair of nuclear-capable B-2 stealth bombers over South Korea. At the time, the North responded by threatening a nuclear attack on the US.
The US is also considering sending a nuclear-powered aircraft carrier to waters off the Korean peninsula next month to join a naval exercise with Seoul, South Korea's Yonhap news agency reported without identifying a source. But officials from US Forces Korea said they had no knowledge of the plan.
The two Koreas remain in a technical state of war after their 1950- 1953 conflict ended in a truce, and the US has about 28,500 troops based in South Korea.
An editorial in the North's Rodong Sinmun newspaper yesterday called for a peace treaty with the US, which is the North's longstanding position. "Only when a peace treaty is concluded between (North Korea) and the US can genuine peace settle in the Korean peninsula," state news agency KCNA quoted it as saying.
The US and China have dangled the prospect of better ties if North Korea gives up its nuclear weapons.
Earlier yesterday, KCNA quoted Mr Kim as saying no one had the right to criticise the North's nuclear tests. "(North Korea'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 US-led imperialists," it quoted Mr Kim as saying.
Mr Kim's comments were in line with the North's official rhetoric blaming the US for deploying nuclear weapons on the Korean peninsula to justify its nuclear programme, but were the first by its leader since last Wednesday's blast.
The US has said it has no nuclear weapons stationed in South Korea.
South Korea continued to conduct high-decibel propaganda broadcasts across the border into the North yesterday.