The United States military is to fly a new type of unmanned spy plane near the North Korean border.
The Shadow-200 UAV has already been used in Iraq
The Shadow-200 Unmanned Aerial Vehicle (UAV) will fly on Friday from an army base near the South Korean capital, Seoul, according to a US military statement.
The planes, which will help monitor the Demilitarised Zone between the two Koreas, are likely to trigger an angry response from Pyongyang.
North Korea has been locked in a stand-off with Washington over its suspected nuclear weapons programme, and it regularly accuses the US of making preparations for war.
Earlier on Tuesday, North Korea dismissed calls from the United Nations' nuclear watchdog to abandon its nuclear programme, saying the US was using the agency for its own ends.
The Shadow-200 UAV flights would mark the first time such unmanned aircraft had been used in South Korea, US army spokesman Lieutenant-Colonel Steven Boylan said.
He agreed that North Korea was likely to issue an angry statement in response to the flights.
According to an army statement, the flights were part of a planned $11bn
investment in 150 programmes to "enhance US defensive capabilities (in South Korea)".
More than 35,000 US troops have been stationed in South Korea since the end of the 1950-1953 Korean war.
Shadow spy planes are designed to track enemy movements, and were first used in US operations in Iraq.
The Shadow-200 UAV, which has a wings-span of 4 metres [13 foot], carry surveillance equipment which can operate at day or night.
"This system gives us a marked advantage over the
enemy," said Captain Samuel Hall of the US Second Infantry
"With the Shadow, we now have the ability to see
first, understand first and finish decisively," he told the Associated Press news agency.
The US announcement about the spy planes came as North Korea issued a blunt response to the UN's nuclear watchdog, the International Atomic Energy Agency (IAEA).
Last Friday, the IAEA passed a resolution urging North Korea to "completely dismantle" its development of nuclear arms.
But according to North Korea's KCNA news agency, this proposal "does not deserve even a passing note".
North Korea has accused the IAEA of being manipulated by the US, which has led opposition to Pyongyang's nuclear ambitions.
The nuclear crisis was "a product of the US' hostile policy" towards North Korea, according to KCNA.
Last month, North Korea and the US met at six-nation talks to defuse the crisis, but the discussions ended without agreement.
China, North Korea's closest ally, is trying to arrange a new round of talks.