North Korea said the assembly of the satellite and rocket it plans to launch within the next week should be completed Tuesday, setting the stage for a move that has been widely criticized by other nations.
The controversial launch will take place sometime between Thursday and Monday, the previously outlined window, Ryu Kun Chol, a senior North Korean space official said at a news conference in Pyongyang.
North Korea says the operation, announced last month, is for peaceful purposes. But Japan, the United States and South Korea see the launch as a cover for a long-range ballistic missile test.
Ryu, the deputy director of the Space Development Department of the Korea Space Technology Committee, said Tuesday that it was unreasonable to claim this was a ballistic missile test in disguise.
The act of firing the long-range rocket would breach U.N. Security Council resolutions, and Washington has suspended a recent deal to provide food aid to North Korea as a result. Japan has said it will shoot down any part of the rocket that enters its territory.
The South Korean defense minister, Kim Kwan-jin, discussed the upcoming rocket launch with his U.S. counterpart, Leon Panetta, by phone, an official from the South Korean Defense Ministry official said Tuesday.
Kim and Panetta both agreed that the launch would be a "grave provocation," the official said.
South Korea will "respond with appropriate countermeasures," the country's Reunification Ministry said in a statement without giving further details.
The last time Pyongyang carried out what it described as a satellite launch, in April 2009, the U.N. Security Council condemned the action and demanded that it not be repeated.
Adding to the tensions, a recent report from South Korean intelligence officials suggests North Korea is planning a new nuclear test in the area where it staged previous atomic blasts.
The South Korean intelligence report noted that the two previous rocket launches that Pyongyang said were to put satellites in orbit were followed a few weeks or months later by nuclear tests.
China, North Korea's closest ally and largest provider of aid, has expressed concern about the planned launch. Beijing says it has held talks with Pyongyang on the matter, but they appear to have had little effect on the North's plans.
"China strongly encourages everyone involved to remain calm and reasonable," said the Chinese foreign minister, Yang Jiechi, according to a report Monday by the official Chinese news agency, Xinhua. "These issues need to be worked out in a diplomatic and peaceful manner."
Analysts say the current trajectory of the multi-staged rocket's path is north to south over the Yellow Sea, with the main body of the projectile eventually landing in the Pacific Ocean near the Philippines.
President Benigno Aquino III of the Philippines has publicly condemned the launch as a "needless provocation" that could increase tensions in East Asia.
Several airlines operating in the region have said they will change flight routes during the launch window.
Philippine airlines is rerouting more than 10 flights, All Nippon Airlines is changing the paths of five flights, and Japan Airlines is adjusting four.