State media gave few details, but analysts say this is unlikely to be a return to the long-range missile tests seen as a threat to the US.
A similar test last November was viewed as an attempt to pressure the US.
There has been little progress in nuclear talks since the last summit.
In February, Donald Trump and Kim Jong-un met in the Vietnamese capital of Hanoi to discuss denuclearisation, but discussions broke down and both leaders left abruptly.
Last week, Mr Kim said Mr Trump needed to have the “right attitude” for talks to continue.
What is North Korea claiming?
According to the Korean Central News Agency (KCNA) the test was overseen by Mr Kim himself.
KCNA reported that the test was “conducted in various modes of firing at different targets”, which analysts believe means the weapon could be launched from land, sea or air.
Mr Kim said the development was “of very weighty significance in increasing the combat power of the People’s Army”.
The report gave few other details, so it’s not even clear if this was a type of missile – but most observers agree it was probably a short-range weapon.
Last year, the North Korean leader said he would stop nuclear testing and would no longer launch intercontinental ballistic missiles, as Pyongyang’s nuclear capabilities had been “verified”.
Nuclear activity appears to be continuing, however, and satellite images at North Korea’s main nuclear site last week showed movement, suggesting the country could be reprocessing radioactive material into bomb fuel.
The country claims it has developed a nuclear bomb small enough to fit on a long-range missile, as well as ballistic missiles that could potentially reach the mainland US.
North Korea analyst Ankit Panda noted that the latest announcement followed fresh US-South Korean military exercises, describing the reported test as “tit-for-tat”.
‘Pressure? What Pressure?’
Analysis by Laura Bicker, BBC News, Seoul
This launch was fairly low-key by North Korean standards. It doesn’t appear to be a long-range missile, nor was it a nuclear test.
This means Kim Jong-un can say he’s keeping his promise not to fire these weapons – while developing new ones.
Perhaps it’s not a direct challenge to Donald Trump. But it could be designed to provoke some thought in the White House and warn them of what could follow if a deal isn’t done soon.
The current thinking in Washington seems to be that as long as there’s no testing, and the sanctions remain in place, there’s no rush. The US also seems to be under the impression that it’s holding all the cards in this negotiation. This launch is a reminder that North Korea is continuing to create weapons despite facing tough economic sanctions.
Pyongyang appears to be shrugging and saying, pressure? What pressure?!
Let’s not forget that these launches send a message to the people of North Korea. There are reports that the state is facing food shortages. Kim Jong-un needs to rally his people and his resources. A show of military strength and a reminder that they face a common enemy will aid that cause.
The test may also ensure North Korea’s military capabilities remain near the top of Mr Trump’s intelligence briefings. As he heads into an election year, he won’t want to see headlines on a series of missile tests – a problem the US president claimed to have solved.
Where do the nuclear talks stand?
Very little has moved since the US and North Korean leaders walked out of talks in Hanoi – apart from rhetoric.
The US said talks broke down because North Korea wanted all sanctions lifted in exchange for scaling back its nuclear capacity, but Pyongyang disputes that.
In his most recent comments, Mr Kim urged Mr Trump to pursue a deal that was “mutually acceptable” but also spoke of his excellent ties with the US leader. Mr Trump responded by tweeting generous praise of Mr Kim and also welcomed the idea of another summit.
Earlier this week the State Department announced that Stephen Biegun, its special envoy for North Korea, was heading to Moscow for meetings “with Russian officials to discuss efforts to advance the final, fully verified” denuclearisation of North Korea.
It came as speculation of a possible future meeting between Kim Jong-un and Vladimir Putin intensified.