Ambassador Yukio Takasu says Japan wants a "clear, firm and unified" response
An emergency meeting of the United Nations Security Council to discuss North Korea's rocket launch has ended without agreement.
As divisions emerged, diplomats said the council would continue talks. It may take days for a deal, analysts say.
Washington and Tokyo are seeking a strong response, but Beijing and Moscow have called for restraint.
Pyongyang says it launched a satellite early on Sunday but its neighbours say it was testing missile technology.
The US, South Korea and Japan have all condemned the launch from the Musudan-ri base in the north-east of the communist country.
They say it violates a UN Security Council resolution adopted in October 2006 which bans North Korea from carrying out ballistic missile activity.
Susan Rice, the US envoy to the UN, called Pyongyang's move a "clear-cut violation of [resolution] 17-18", while her Japanese counterpart said Tokyo was seeking a "clear, firm and unified" response.
But, says the BBC's Laura Trevelyan, who is at the UN in New York, countries such as China and Russia disagree.
There was no general agreement at the council on whether North Korea was in breach of the resolution, let alone on whether it should be punished, our correspondent says.
Zhang Yesui, China's envoy to the UN, said that the world should refrain from taking action that might lead to increased tension.
Any action by the Security Council should be "cautious and proportionate", he said.
Given the divisions between the major powers new sanctions seem unlikely, our correspondent says.
So what the US and Japan want is a resolution that reinforces sanctions already in place against Pyongyang; the question is whether China and Russia will even agree to that, she adds.
An agreed position could take several days to emerge.
The Japanese government, meanwhile, said it would be considering possible new bilateral sanctions against North Korea over the course of the next few days.
North Korean state media said that leader Kim Jong-il had visited the General Satellite Control and Command Centre to observe the launch.
It said a communications satellite had been successfully placed in orbit and was transmitting data.
But the US military said that the rocket's payload, along with its booster stages, landed in the Pacific Ocean.
Pyongyang's neighbours are concerned about the potential military use of the launch vehicle, and believe North Korea's real aim was to test the long-range Taepodong-2 missile.
They believe it could put parts of the US within the communist nation's military reach.
North Korea first tested a Taepodong-2 in July 2006. It failed less than a minute after lift-off.
Three months later, Pyongyang carried out a nuclear test.
International talks involving the US, South Korea, Japan, Russia and China on an aid-for-nuclear disarmament deal are currently stalled.