North Korea has installed the first stage of a long-range rocket it plans to launch this month on the launch pad, defying international calls to cancel the mission.
North Korea announced on Saturday that it would carry out its second long-range rocket launch this year between 10 and 22 December.
The United States and its key Asian allies South Korea and Japan have condemned the launch as a disguised ballistic missile test that violates United Nations resolutions triggered by Pyongyang's two nuclear tests in 2006 and 2009, AFP reports.
The first stage has been placed in position at the North's Sohae satellite launch station, a South Korean government source told Yonhap news agency.
Japan cancelled scheduled diplomatic talks with North Korea and has reportedly issued orders to shoot down the missile if it strays into Japanese territory.
North Korea insists it is a purely "peaceful, scientific" mission aimed at placing a polar-orbiting earth observation satellite in orbit.
In a notification to neighbouring countries, Pyongyang said the launch timing would be between 7am and midday on any day in the given window, Yonhap quoted a foreign ministry official as saying.
According to the notice, the first stage would fall into the Yellow Sea off the Korean peninsula's west coast and the second would come down in the sea 190km east of the Philippines.
AFP reports South Korea's chief nuclear envoy Lim Sung-Nam was to meet with ambassadors from China, Russia and Japan in Seoul on Monday to discuss the planned launch, a foreign ministry official said.
China, the North's closest ally, has expressed "concern" at the launch plan, with the foreign ministry urging "relevant parties (to) act in a way that is more conducive to the stability of the Korean peninsula".
Mr Lim also plans to visit the United States on Tuesday for talks with his US counterpart, Glyn Davies.