Reclusive North Korea pressed ahead Friday with final preparations to blast a multistage rocket over Japan as world leaders scrambled to forge a united stance on how to punish it for the launch. Saturday is the start of a five-day window during which the North says it will send a communications satellite into orbit. The US, South Korea and Japan believe the communist country is really testing long-range missile technology - a move they have warned would violate a 2006 UN Security Council resolution banning the North from ballistic activity. The launch has sparked international alarm because the North has admitted it has nuclear weapons and has repeatedly broken promises to shelve its nuclear program or halt rocket tests. President Barack Obama, appearing with the French president in Strasbourg, France, said the launch is provocative and should be stopped, adding that the US will "take appropriate steps to let North Korea know that it can't threaten the safety and security of other countries with impunity." A successful launch would mean the renegade state has a long-range missile capable of delivering weapons of mass destruction, said Kim Sung-han, an international affairs professor at Seoul's Korea University, although it is unclear if the North has been able to shrink its warheads enough to fit on a rocket. It would also help North Korea's exports of missiles or missile parts, Kim said - a key consideration for one of the world's poorest countries. North Korea already has medium-range missiles that can reach Japan, over which the North has said the missile will travel. Tokyo is bracing for the possibility that debris could fall around its northern coast. Japan has deployed warships with anti-missile systems off the coast, set up Patriot missile interceptors and established a system to warn residents when the rocket is approaching. Japan says it has no intention of trying to shoot down the rocket itself, which is expected to reach its territory 10 minutes after liftoff. "It is a threat to the security of Japan," Yukio Takasu, Japan's UN ambassador, said Thursday, adding that the launch announcement "raises tensions in our region, and also internationally." But some people living in the danger zone weren't worried. "We never know what North Korea is thinking about, but I'm not concerned as long as it doesn't affect my work," said Manabu Miura, 59, a fisherman in Kamo, Japan. "I'll go fishing." South Korea is considering elevating its military alert status to the second-highest level amid concerns the North could also fire a barrage of shorter-range missiles along with the rocket. Fueling at the launch pad in Musudan-ri appears nearly complete, South Korea's Yonhap news agency cited an unidentified government official as saying. Experts say the launch would likely follow quickly because rocket fuels are generally highly corrosive. Cloudy conditions are forecast for the launch area Saturday but no strong winds that could force a delay. Japanese Prime Minister Taro Aso said Thursday that a Saturday launch was likely. A senior US intelligence official also told The Associated Press that North Korea was on track for liftoff then. The official spoke on condition of anonymity to discuss intelligence issues. Diplomats scrambled to find ways to persuade North Korea to cancel the launch. Even China, the North's closest ally, said it was working to avert a liftoff while urging all parties to avoid aggravating the tense situation. Chinese President Hu Jintao met Friday with his South Korean counterpart, Lee Myung-bak, who has been pushing for swift punishment if the launch goes ahead; Japan and other nations plan to request an emergency session of the UN Security Council as soon as this weekend. A strong united response likely would prove difficult, because China holds veto power in the council and could argue that the 2006 ban does not extend to nonmilitary space missions. Hu and Lee agreed the "rocket launch would negatively affect peace and stability in Northeast Asia and there should be a discussion among related countries" after the launch, Lee's office said. But their statement stopped short of mentioning a Security Council referral or sanctions. North Korea has warned against any efforts to censure it, claiming it has the right to the peaceful use of space. It also has threatened retaliation against any efforts to intercept the rocket. North Korea has repeatedly used brinksmanship to wring aid and concessions from the West and could be doing the same thing this time. The North has also detained two Americans and a South Korean and could use them as bargaining chips. Yang Moo-jin, a professor at Seoul's University of North Korean Studies, said North Korean leader Kim Jong Il also appears to be trying to use the launch to solidify internal unity, with the event serving as "celebratory fireworks" ahead of his re-election as leader next week. At a rally in central Seoul, about 100 activists torched a North Korean flag and a missile replica plastered with Kim's portrait.