NATO Secretary General Jaap de Hoop Scheffer described North Korea's rocket launch as "highly provocative", joining international outcry against the move.
"I condemn the launch by North Korea of a multistage rocket," Scheffer said in a statement.
"This launch is highly provocative" and violates a UN Security Council resolution barring Pyongyang from developing or launching ballistic missiles, he added.
"This launch will only deepen concern about North Korea in the region and beyond, and complicated the six-party talks," Scheffer said, referring to disarmament talks involving five nations and North Korea.
Scheffer's remarks echo outrage aired by US President Barack Obama and other world leaders after the launch of a long-range rocket by the isolated, nuclear-armed Stalinist state.
"I call on North Korea to cease such provocative actions and to respect immediately a moratorium on all long-range missile launches," Scheffer said.