SEOUL - The Republic of Korea (ROK) fired warning shots on Saturday at a patrol boat from the Democratic People's Republic of Korea (DPRK), as the reunion continues for families separated by the 1950-1953 Korean War, a sign of a thaw in inter-Korean relations.

The DPRK ship violated the northern limit line (NLL), which Pyongyang has never accepted as a sea boundary as it was drawn by US-led forces after the Korean War ended, at about 3:30 pm local time on Saturday, Yonhap news agency reported on Sunday citing military officials.

While clamping down on fishing boats, the DPRK military ship sailed south several hundred meters away from the NLL, according to the ROK military authorities.

Seoul's navy vessels fired five warning shots with 40-mm machine gun at the DPRK boat, which returned back minutes after the firing.

There was no more clash between the two sides, a military official was quoted as saying by Yonhap.

Spokesman of the DPRK's Committee for Peaceful Unification of Korea said Sunday that the ROK military conducted provocations against the DPRK ship on a "normal mission" of maritime operations.

The spokesman's remarks, carried by the DPRK's KCNA news agency, denounced the warning shots as "intentional provocative acts" to re-ignite tensions on the Korean peninsula with military clashes in the West Sea waters. The maritime skirmish came amid the ongoing family reunion event, which was agreed between the two Koreas in late August after top-level military talks to defuse tensions that had pushed the peninsula to the brink of armed conflict.

A total of 254 elderly ROK nationals from 90 families on Saturday crossed the inter-Korean border by bus into the DPRK's scenic resort of Mount Kumgang to meet their long-lost relatives from the other side of the border. Coming from the DPRK to take part in the highly charged event was 188 people.

On the second day of the three-day reunion, the separated families held the first private face-to-face meeting in the morning, for the first time since the Korean conflict ended with armistice. Since the war, no direct exchange of letters and telephone calls has been allowed between peoples of the two sides.

After the luncheon gathering, they are scheduled to meet each other in public in the evening before coming back to their respective home Monday, according to Seoul's unification ministry.

The first round of the humanitarian event ran for three days through Thursday at the mountain resort.

After the family reunion began as agreed, expectations had spread that the ROK and DPRK would hold an inter-governmental dialogue in Seoul or Pyongyang, which top-level military officials from both sides had agreed in late August.

The DPRK recently offered to ROK to sign a peace treaty, instead of an armistice that has made the two Koreas remain technically at war, but Seoul hasn't made clear its stance about the proposal.

Seoul repeatedly urged Pyongyang to return back to the six-party talks on DPRK's nuclear program.