North Korea is almost certain to launch its long-range rocket, possibly as early as Saturday if weather allows, South Korean President Lee Myung-bak said on Friday, promising a "strong and stern response." "I think it's almost certain North Korea will fire the missile," he told a small group of reporters in London where he had attended the G20 summit, Reuters reported. He also said the health of North Korean leader Kim Jong-il, widely thought to have suffered a stroke last year, appeared to be improving and that he had a continued hold on power. "We favour sending out a very strong and stern message to the North Koreans that the international community does not condone nor will it accept North Korea engaging in such actions." But Lee offered no substantial measures to respond to the missile launch scheduled for between April 4-8, which many consider will be to test a long-range ballistic missile that could carry a warhead as far as the United States and which would contravene U.N. resolutions. North Korea says it is sending a communications satellite into space for peaceful purposes. "We don't have anything in place to respond (to a launch)," Lee said, adding the issue would go to the U.N. Security Council.