The UN Security Council is to hold an emergency meeting later following North Korea’s launch of a long-range rocket.
The meeting was requested by South Korea, Japan and the US to agree on a collective response to the launch.
Pyongyang said it fired the rocket to place a satellite in orbit, but critics believe the real purpose was to test a ballistic missile.
Sunday’s launch comes weeks after North Korea held a fourth nuclear test – both acts violate UN resolutions.
The launch of the rocket was hailed by North Korean media as a “fascinating vapour… trailing in the clear and blue sky in spring of February on the threshold of the Day of the Shining Star”.
A statement said a new Earth observation satellite, Kwangmyongsong-4, had successfully been put into orbit less than 10 minutes after lift-off from the Sohae space centre in North Phyongan province.
Hailing it as part of the country’s peaceful space programme, a state TV newsreader said the launch had been ordered by North Korea’s leader Kim Jon-un and more satellite launches were planned for the future.
South Korean MPs were told in a closed-door briefing by the country’s spy agency later on Sunday that the launch should be treated as a ballistic missile test as the satellite it put into orbit would be useless.
The payload was presumed to weigh 200kg (440lbs), double the size of the one launched in 2012, but much lighter than the 800-1,500kg usual for a satellite.
They were also reportedly told that North Korea has the technology for intercontinental ballistic missiles and is preparing a fifth nuclear test, South Korean news agency Yonhap reported.
Analysis: BBC’s John Sudworth in Beijing
Sunday’s launch does not significantly alter the strategic balance of power in North East Asia. It is not the first time North Korea has attempted to put an object into space using a long-range rocket.
But it is nonetheless a highly-provocative act, hence the reaction from Seoul, Tokyo and Washington, calling it “unforgivable” and “intolerable”.
The significance is in the timing, with the launch coming just a month after the North’s fourth nuclear test and with the UN Security Council in the middle of weighing its sanctions response.
Beijing too is unlikely to be under any illusion that the real purpose here is the test of the missile itself. After all, if Pyongyang wanted to put up satellites it could pay its old ally to do so at a fraction of the price.
But China is, as always, treading a careful line, issuing a nuanced statement of “regret”. Its biggest fear is pushing an already isolated and heavily sanctioned neighbour towards economic and political collapse.
And so while each such rocket launch takes North Korea one more step towards its stated goal of a deliverable nuclear weapons system (although probably still years away) the international impasse over what to do about it is likely to continue.
North Korea satellite launch – world reaction
Why did Kim fire a rocket now?
UN Secretary-General Ban Ki-moon called it “deeply deplorable”, while Nato said it was in “direct violation” of five UN Security Council resolutions.
China – a key ally of Pyongyang’s – said it “regrets” North Korea’s actions but urged “the relevant parties” to “refrain from taking actions that may further escalate tensions on the Korean peninsula”.
US Secretary of State John Kerry warned of “significant measures to hold the DPRK [North Korea] to account.”
Contenders for the Republican ticket in the US presidential election this year were asked for their reaction during a debate in New Hampshire.
Donald Trump said China was the key. “I would get on with China. Let China solve that problem.” Jeb Bush said he would not rule out an attack on North Korea. “If a pre-emptive strike is necessary to keep us safe, then we should do it.”
North Korea last fired a long-range rocket in 2012 to put, what it said was, a communications satellite into orbit. But experts say no signal has ever been detected.
UN Security Council resolutions ban the state from carrying out any nuclear or ballistic missile tests.
The North insists its space programme is purely scientific in nature but the US, South Korea and even ally China say the rocket launches are aimed at developing inter-continental ballistic missiles.
North Korea’s rocket launches
- February 2016: Launch of rocket reportedly carrying satellite
- May 2015: North Korea announces it has successfully tested a submarine-launched missile for the first time, but scepticism is then poured on the claim
- Dec 2012: North Korea launches three-stage rocket, says it successfully put a satellite into orbit; US defence officials confirm object in orbit
- Apr 2012: Three-stage rocket explodes just after take-off, falls into sea
- Apr 2009: Three-stage rocket launched; North Korea says it was a success, US says it failed and fell into the sea
- Jul 2006: North Korea test-fires a long-range Taepodong-2 missile; US said it failed shortly after take-off