North Korea has begun final preparations for its controversial long-range rocket launch and could fire the weapon as early as Saturday, South Korean media reported on Friday.
"North Korea seems to have almost finished fuelling the rocket, so it is highly likely it will launch it," The Korea Times quoted an anonymous government official as saying.
South Korean President Lee Myung-bak plans to convene a meeting of the National Security Council, and would send a special envoy to North Korea, the paper said.
Washington and Seoul suspect Pyongyang is preparing to test a Taepodong-2 missile, which is theoretically capable of reaching Alaska and carrying a nuclear warhead, under the cover of a satellite launch. Its first test of such a missile in 2006 failed.
Japan, which feels threatened by the North Korean rocket, has warned that it will extend its trade sanctions against the Pyongyang regime if the missile is fired. The sanctions are set to expire April 13.
On Wednesday, North Korea warned Japan that it would "mercilessly deal deadly blows" on its neighbour, if Japan were to shoot down the rocket.