North Korea has fired an unidentified type of projectile, South Korea’s Yonhap news agency reports.
The missile was launched at 07:55 local time (22:55 GMT Saturday) and flew east towards the Sea of Japan, South Korean defence officials say. Initial reports had described it as ballistic missile.
Pyongyang has conducted a number of nuclear tests in the past year.
North Korea’s repeated missile and nuclear tests and aggressive statements continue to alarm and anger the region.
The missile launch from Banghyon air base in North Pyongan province on the country’s west coast is the first such test since US President Donald Trump took office.
North Korea conducted its fifth test of a nuclear device last year, and claims it is capable of carrying out a nuclear attack on the US, though experts are still unconvinced that its technology has progressed that far.
It has also said in recent weeks that it has a new intercontinental ballistic missile, capable of reaching the US mainland, which it is prepared to test launch at any time.