SEOUL - The Democratic People's Republic of Korea (DPRK) had test-launched an intermediate-range ballistic missile, but it ended in a failure, Seoul's military said Sunday.

South Korea's Joint Chiefs of Staff (JCS) said in a statement that the DPRK fired what is believed to be a Musudan missile at about 12:33 pm local time on Saturday (0333 GMT) near an airport in the DPRK's northwestern North Pyongan province.

The test-launch, the JCS said, failed as the missile exploded soon after its liftoff.

The failed launch came on the day that the United States and Republic of Korea (ROK) wrapped up their joint naval exercises that kicked off on Monday in all of the three seas around ROK.

The US military mobilized its nuclear-powered aircraft carrier USS Ronald Reagan to participate in the week-long drill, which also involved seven US warships and some 40 ROK battleships as well as fighter jets, maritime patrol airplanes and helicopters.

The missile launch was the latest in a series of provocations by the DPRK following its fifth nuclear test last month. Pyongyang said on Sept 9 that it successfully tested a nuclear warhead that can be mounted on ballistic missiles.

The DPRK has claimed it already secured a nuclear missile technology capable of striking the US mainland. The medium-range Musudan missile is known to have a range of 3,000-4,000 km that can reach the US military base in Guam.

On Sept 5, Pyongyang launched three Rodong missiles from its east coast as part of efforts to enhance its capability to deliver nuclear warhead. Rodong missiles are known to be capable of striking US military bases in Japan.

The DPRK is expected to attempt another launch of a Musudan missile as the latest test failed. After several failed attempts, the country conducted its first successful launch of the missile on June 22, flying as high as 1,413.6 km and traveling about 400 km.

The ROK military has closely monitored the moves of DPRK forces, with all possibilities left open for another nuclear test and the launch of a long-range ballistic missile.

Increased activity was detected in the DPRK's main Punggye-ri nuclear test site, indicating preparations for another nuclear detonation in the near future.

In its Tonchang-ri rocket base, which Pyongyang calls Sohae Satellite Launching Station, the moves of personnel and vehicles were spotted. It boosted worries about the test-launch of a long-range rocket.

The DPRK's fourth nuclear test on Jan 6 was followed by the launch on Feb 7 of a long-range rocket. Seoul's military is worried about another long-range rocket launch by the end of this year following the fifth nuclear test in early September.