The US and its allies slammed North Korea for launching a missile with President Barack Obama calling it a ‘provocative act’ in violation of Pyongyang's international obligations and vowing to prevent the proliferation of weapons of mass destruction (WMD) through a strong global response.

"The launch today of a Taepodong-2 missile was a clear violation of United Nations Security Council Resolution 1718, which expressly prohibits North Korea from conducting ballistic missile-related activities of any kind," Obama, who is in Czech capital Prague, said in a statement.

"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.

Later addressing a security conference, Obama said the time has come for a "strong international response" to the North Korean action.

"North Korea must know that the path to security and respect will never come through illegal weapons. All nations must come together to build a strong global regime. That's why we must stand shoulder-to-shoulder to pressure the North Koreans to change course," he said.

His remarks came after North Korea defied weeks of Western pressure and launched a long-range rocket, "successfully" placing a communications satellite in space.