Seoul, May 28 (IANS): South Korean and US military aircraft have staged regular combined live-fire drills to strengthen readiness against North Korean threats, Seoul's Air Force said on Tuesday, amid heightened tensions over Pyongyang's failed satellite launch.

More than 90 aircraft, including the South's F-35A stealth fighters and the US A-10 attack aircraft, have been mobilised for the four-day exercise that began on Monday over waters off South Korea's west coast, according to the Air Force, Yonhap news agency reported.

The exercise is focused on strengthening the participating pilots' strike capabilities and bolstering readiness against possible enemy provocations, it said.

This week's drills will take place in the wake of North Korea's botched attempt to launch a military spy satellite into orbit on Monday night.

North Korea's rocket exploded minutes after liftoff from the major satellite launch site on the northwestern coast, according to South Korea's military.