North Korea argued Saturday that South Korean navy warships have increasingly violated their disputed western sea border, heightening tension on the Korean Peninsula.

"The South Korean puppet navy warships' intrusion into the territorial waters of the DPRK side in the West Sea of Korea has recently been on explosive increase," the North's state-run Korean Central News Agency said in an English-language report monitored in Seoul. DPRK stands for the Democratic People's Republic of Korea, North Korea's official name.

The KCNA argued that 101 navy warships infiltrated the inter-Korean maritime border on 81 occasions in April, which is almost twofold tallied in March.

"Such intrusion has created the danger of military conflict in the hotspotwaters in the West Sea of Korea beset with constant tension," the KCNA said.

Tensions remain high along the sea border which has been a constant source of conflict between the two Koreas, still technically in a state of war. In 1999 and 2002, the two Koreas engaged in bloody naval battles, resulting in heavy casualties on both sides.

Pyongyang further argued the alleged intrusions coincide with joint military exercises between South Korea and the United States, saying that military provocation is escalating to the maximum.

Seoul and Washington kicked off their annual joint drills -- Key Resolve and Foal Eagle -- in March. The two-month combat exercise Foal Eagle runs through the end of April.

Earlier in the day, North Korea launched a ballistic missile which apparently exploded minutes after liftoff, disregarding increased pressure from the Donald Trump administration. (Yonhap)