"With this provocative act, North Korea has ignored its international obligations, rejected unequivocal calls for restraint, and further isolated itself from the community of nations," he said.
A senior South Korean foreign ministry official called the North's rocket a "space vehicle" which, he believed, carried a satellite.
"We believe North Korea fired a rocket carrying a satellite," the official was quoted as saying by Yonhap news agency. However, it did not necessarily mean that the launch was a success.
The Taepodong-2 missile is believed to have a range of more than 6,000 kilometres, capable of reaching US territory, but a test launch in July 2006 apparently failed.
Image: DigitalGlobe's QuickBird satellite image shows the North Korea rocket launch facility in Musudan Ri, North Korea.
Photograph: DigitalGlobe/Handout/Reuters