PYONGYANG, North Korea - North Koreans have been celebrating in the streets today, after the launch of the country's first satellite in space. But elsewhere around the world, leaders are reacting with concern.

The surprising, successful launch of a three-stage rocket raises the stakes in the international standoff over North Korea's expanding atomic arsenal. The rocket is similar in design to one that would be capable of carrying a nuclear-tipped warhead as far as California.

The U.N. Security Council is condemning the launch, and says it will consider "an appropriate response." The White House calls it a "highly provocative act that threatens regional security." Even China, the North's most important ally, is expressing regret.

But in North Korea's capital, residents poured into the streets after the announcement, to celebrate the launch by dancing in the snow.

The launch was North Korea's fourth attempt since 1998. A launch attempt in April failed in the first of three stages, raising doubts about whether the North could fix what was wrong in just eight months. But those doubts have now been erased.