SEOUL (Reuters) - North Korea accused the United States on Thursday of planning a nuclear attack in a report which came as Secretary of State Hillary Clinton flew to Seoul for talks on defusing Pyongyang's military threat.

It was the latest in increasingly angry rhetoric by the reclusive state, which earlier in the day said it was ready for war with South Korea.

The U.S. bellicose quarters are pushing ahead with the moves for rounding off the preparations ... in a bid to make a pre-emptive nuclear strike, the North's official media said.

The U.S. is talking about what it called 'dialogue' and 'peace' on the Korean peninsula but, in actuality, seeking to escalate the military confrontation, the KCNA news agency quoted a commentary in the state's communist party newspaper as saying.

The prickly North, which has repeatedly threatened in recent weeks to reduce the South to ashes, is thought to be readying its longest-range missile -- which could reach U.S. territory -- for launch in what analysts say is a bid to grab the new U.S. administration's attention and put pressure on Seoul.

Clinton said in Tokyo on Tuesday, at the start of her first foreign trip since taking office, that a North Korean missile launch would be very unhelpful. [ID:nSP261436]

The South's foreign minister warned a launch would be met by sanctions and further isolation. The two Koreas are technically still at war, never having reached a formal peace treaty to end their 1950-53 conflict.

Seoul has all but cut off aid to its neighbor because Pyongyang has been dragging its heels over ending its nuclear weapons program.

In a reminder of the North's dire plight, the South's unification minister told parliament the state fell about 20 percent short of producing the minimum food needed to feed its 23 million people despite having one of its best harvests in years.

MISSILE TESTS

Reports in the South said North Korea has been assembling its Taepodong-2 missile, which is designed to carry a warhead as far as Alaska. The same missile fizzled and blew apart seconds after it was launched for the first and only time in 2006.

South Korea's defense minister was quoted by local media as saying the North could test-launch the missile in about two or three weeks. A leading local daily quoted intelligence sources as saying it could be as early as next week.

South Korean officials have said they are also worried about North Korea holding a short-range missile test toward a contested Yellow Sea border off the west coast of the peninsula which has been the scene of deadly naval fights between the rival Koreas.

Analysts said the North may provoke a minor skirmish but did not expect a major conflict because Pyongyang's huge but ill-equipped army is little match for South Korea and its major ally the United States, which positions about 28,000 troops on the peninsula.

Just before Clinton touched down in Tokyo this week, North Korea issued a fresh missile threat by saying it had the right to launch its longest-range rocket, which Pyongyang contends is at the center of its peaceful space program.

Clinton arrives in Seoul late on Thursday from Indonesia and will hold discussions on Friday with top South Korean officials before going to China.

(Additional reporting by Jack Kim)

(Editing by Jonathan Thatcher and Valerie Lee)

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