The B-2 stealth bombers flew practice runs over South Korea Thursday, dropping dummy munitions on an island range. A nuclear-capable B-52 bomber made a similar run earlier this week.

"This mission by two B-2 Spirit bombers assigned to the 509th bomb wing … demonstrates the United States' ability to conduct long-range, precision strikes quickly and at will," the United States Forces in Korea said in a statement.

The stealth bombers flew from a US airbase in Missouri and returned home after dropping their dummy munitions. It was unclear whether the stealth bombers have been used in past drills with South Korea, but it is the first time the military has announced their use.

Increased tension

The flights come after North Korea said it would attack bases in the Pacific following the US-led effort to impose sanctions on the country for conducting its third nuclear test in February.

North Korea put its armed forces on the ready to fight what it says are "hostile" drills by the US and South Korea. The US says the exercises are defensive.

On Wednesday the North said there was no need for communication in a situation "where war may break out at any moment." Earlier this month the country announced that it considers void the armistice that ended the Korean War in 1953.

Joint-run plant operating

A day after the country shut down communication lines ordinarily used to move workers and goods across the border, a North Korean industrial plant run with South Korean know-how was operating normally. The plant, which lies just over the western end of the border, is one of North Korea's only sources of foreign currency.

Blocking South Koreans from getting in and out of the plant, which produced $470 million (366 million euros) worth of goods last year, could have damaged the North's already weak finances.

US Secretary of State John Kerry is expected to travel to Seoul, Tokyo and Beijing next week and State Department spokeswoman Victoria Nuland said discussions over North Korea's behavior will be "front and center."

dr/mkg  (Reuters, AP, dpa)