An American strategic bomber landed in South Korea on Wednesday to remind Pyongyang of its powerful military assets in the region, US official sources said.
The move comes a day after North Korea claimed it had successfully tested a new, high-powered rocket engine which the South said was designed to demonstrate progress towards attaining a long-range missile.
Television footage showed two supersonic B-1B Lancers flying low over the US Osan Air Base at Pyeongtaek, 64 kilometres (40 miles) south of Seoul.
One of the aircraft flew back to the Andersen Air Force Base in Guam, while the other landed at Osan, Yonhap news agency said.
“The bond between the United States and the Republic of Korea (South Korea) is ironclad and the strength of that commitment will not be shaken by North Korea’s aggressive behaviour,” said Lieutenant General Thomas W. Bergeson of the US Air Force.
“What we are showing today is just one tool we have to choose from a wide array of options. The alliance grows stronger every day and we remain prepared to defend and to preserve the security of the Korean Peninsula and the region,” he said.
The US flew two planes over South Korea last week, days after the North’s fifth nuclear test, but they returned swiftly to Guam.
Critics dismissed the move as cursory in the light of an apparent quickening in the pace of North Korea’s nuclear and missile testing program.
It was not clear how long the Lancer that landed at Osan would stay.
South Korea is home to around 28,500 US troops and numerous bases.
The B-1 Lancer is a four-engine strategic bomber that can reach speeds of Mach 2.
It is capable of carrying the largest payload of both guided and unguided weapons in the US Air Force inventory.
“It can rapidly deliver massive quantities of precision and non-precision weapons against any adversary, anywhere in the world, at any time,” US Forces Korea said in a press statement.