"A squadron-size unit of stealth jets, numbering somewhere between 12 and 24, will be deployed in Gunsan airbase (on the southwestern coast of South Korea)," a US military spokesman said.

"They will take part in a drill aimed at getting themselves familiar with geographic peculiarities. They will stay here for three or four months," he said.

Brigadier General Nam Dae-Yeon, a spokesman for the South Korean Defense Ministry, said US military authorities notified South Korea last month of the deployment of its Nighthawk stealth jets to an air base in South Korea.

The Stealth fighter bombers also took part in a military training exercise in South Korea last year, prompting angry protests from North Korea.

South Korea hosts 37,500 US troops as deterrence against North Korea. Last month, Washington said it would cut its troop level in South Korea by one third under a global redeployment plan, prompting security concerns among South Koreans.

The United States and its allies have been locked in a 20-month standoff over North Korea's nuclear weapons programme.

WAR.WIRE