Two US supersonic bombers flew over South Korea on Wednesday, with one of them landing at an air base 40 km south of the capital, the second such flight since North Korea's Sept. 9 nuclear test.
US Forces Korea said in a statement the flight by a pair of B-1B Lancer strategic bombers based in Guam was a show of force and of US commitment to preserve the security of the peninsula and the region.
The United States, which has about 28,500 troops in South Korea, flew two B-1 bombers on Sept. 13 escorted by US and South Korean fighter jets in a show of solidarity with Seoul, Reuters reported.
The North condemned the earlier flight as an armed provocation that mobilized "ill-famed nuclear killing tools". It did not immediately respond to Wednesday's flight.
North Korea has ignored global condemnation since conducting its fifth nuclear test on Sept. 9, and this week said it had successfully tested a new rocket engine that would be used to launch satellites, again in violation of UN sanctions.
The leaders of the United States and China, which is the North's main diplomatic ally and economic benefactor, condemned the latest nuclear test and pledged to step up cooperation at the United Nations and in law enforcement channels.
UN diplomats say the two countries have begun discussions on a possible UN resolution in response to the latest nuclear test, but China has not said directly whether it would support tougher steps against North Korea.
South Korean Prime Minister Hwang Kyo-ahn told parliament it was pushing for tightening existing UN sanctions against the North by removing loopholes that allowed it to trade in minerals if it is for subsistence.
North Korea has been testing nuclear weapons and ballistic missiles at an unprecedented rate this year, beginning with its fourth nuclear test in January and including the launch of a satellite in February that was widely seen as a test of long-range ballistic missile technology.
The North's test of a new rocket engine for satellite launchers this week was believed to be part of a long-range missile program, according to the South's military.
North Korea's leader, Kim Jong Un, ordered preparations for the launch of a satellite "as soon as possible" on the basis of the successful test, its state media reported.
North Korea this month fired three missiles that flew about 1,000 km and in August tested a submarine-launched ballistic missile that experts said showed considerable progress.
It also launched an intermediate-range missile in June that experts said marked a technological advance for the isolated state after several failed tests.
South Korean Defense Minister Han Min-koo told parliament the North was developing all types of missiles, from short- to long-range, and its advances were "considerable".
