North Korea has announced plans to launch a satellite later this month, a UN agency says.
Washington described the launch plan as an "egregious violation" of a UN ban on missile launches in the country and called for more sanctions.
North Korea conducted its fourth nuclear bomb test on 6 January, drawing international condemnation.
Critics called Pyongyang's last satellite launch a cover for a test of ballistic missile technology.
The International Maritime Organization (IMO) says it was notified of Pyongyang's plans to launch a satellite between 8 and 25 February.
US Assistant Secretary of State for East Asia Daniel Russel said the planned launch argued "even more strongly" for tougher UN sanctions.
However, North Korea's ambassador to the UK told an event at the Chatham House think tank in September that his country did not fear international criticism.
"We have nothing to be afraid of," Hyon Hak Bong said, NK News reported.
"We will go ahead definitely, surely. If they… pass resolutions or sanctions, this will be viewed as a provocation and… can make the situation worse. I assure you that the launch is for a peaceful purpose."
Analysts say a new launch would allow North Korea to test some - but not all - of the technology needed for a long-range nuclear strike.
"Satellite launches do not give North Korea the opportunity to demonstrate a re-entry vehicle capability, the component of a ballistic missile system that would bring a nuclear warhead back down towards its intended target," said Andrea Berger from the think tank the Royal United Services Institute (Rusi).
"Whether or not they have managed to develop that particular capability without having visibly tested it is a question we simply don't have the answer to."
Last week, US officials said that North Korea appeared to be preparing for a rocket launch, citing increased activity around the Sohae Satellite Launching Station, also known as Tongchang-ri.
Ms Berger told the BBC the launch was part of the build-up to a major political congress later this year.
The seventh Congress of the Workers' Party of Korea will be the first to be held since 1980.
"At that congress we expect Kim Jong-un to demonstrate more clearly what his own ideology and brand as a leader will be," she said.
"He will almost certainly attempt to paint nuclear and missile capabilities as part of that image - so it's not surprising that, ahead of the party congress, he is looking to demonstrate what he hopes will be major successes in advancing North Korea's nuclear deterrent."
North Korea's rocket launches
- 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
The North last conducted a long-range rocket launch in December 2012, successfully putting into orbit an object Pyongyang claimed was a communications satellite with the three-stage Unha-3 carrier.
The UN Security Council subsequently said the launch was a "clear violation" of resolutions banning North Korea from missiles tests, and imposed sanctions.
North Korea has said its space programme is peaceful, but it is believed to be developing an intercontinental ballistic missile that could strike the US.