North Korea has launched a long-range rocket mounted with a satellite Wednesday morning in defiance of expectations that technical problems might delay the mission that drew international attention.

The defiant move comes after the South Korean authorities said the DPRK seems to have removed the three-stage rocket form the launch pad in an apparent attempt to fix technical problems Pyongyang cited when it extended the launch window by one week until Dec. 29.

The first stage of the rocket fell in the Yellow Sea off Byeonsan-bando in South Korea's North Jeolla Province, according to Yonhap News Agency. The Japanese government also said the rocket passed the southern island chain of Okinawa at around 10:01 a.m. local time and fell in waters off the Philippines shortly afterwards.

South Korean President Lee Myung-bak convened the National Security Council meeting immediately after the launch, and intelligence authorities here are reportedly in consultations with their U.S. and Japanese counterparts to track the rocket.

Wednesday's move marks the DPRK's second bid of the year to put a satellite into orbit, which the United States and its key Asian allies call a disguised ballistic missile test. South Korea has expressed "grave concern" over the plan, and Japan had pledged to shoot down the rocket if it threatens its territory.

Pyongyang, whose previous mission in April ended in failure, has countered that its "polar-orbiting earth observation satellite" is for peaceful scientific purposes only.