North Korea says it is extending the launch period for a controversial long-range rocket by a week, until December 29th.

A spokesman for the North's Korean Committee of Space Technology told the official (North) Korean Central News Agency on Monday that scientists found a “technical deficiency in the first stage control engine module of the rocket.”

The committee said on Saturday that it was considering readjusting the timing of the launch, originally scheduled to take off between December 10th and 22nd.

Japan has threatened to shoot down the missile, if it goes off course and has deployed missile interceptors in preparation.

Last Week, Japanese television showed three Aegis destroyers armed with SM-3 missile interceptors reported to be headed for the East China Sea and the Sea of Japan.

Patriot missile interceptors later arrived at Okinawa island, which lies under the missile's projected flight path. Patriot missiles were also positioned behind the defense ministry in Tokyo.

Pyongyang announced earlier this month that it would launch the rocket, supposedly to put a satellite in orbit. Its neighbors and much of the rest of the world have warned against the launch, saying it is really a disguised missile test and banned under United Nations sanctions.

The Security Council condemned a failed North Korean launch in April, during which the rocket disintegrated shortly after takeoff.

Attempted North Korean rocket launches ended in failure in both 2006 and 2009, although Pyongyang claimed success.