SEOUL - A patrol boat from the Democratic People's Republic of Korea (DPRK) briefly crossed the tense western maritime border with the Republic of Korea(ROK) Thursday, local media reported.

The boat violated the sea border while raiding a Chinese fishing boat but retreated at 11:07 am local time following warning messages from?ROK, Yonhap News Agency said citing a military source.

The border, called the Northern Limit Line, is the scene of deadly naval skirmishes between the rival Koreas.

The DPRK refuses to acknowledge the NLL, which was drawn unilaterally by the US-led United Nations Command (UNC) at the end of the 1950-53 Korean War.

Last week,?ROK's President Lee Myung-bak visited a front-line island near the sea border and reaffirmed the country's commitment to its defense.

The DPRK condemned Lee's trip and reiterated it would only recognize a military demarcation line drawn by Pyongyang.