(Reuters) - High-ranking military officials from North and South Korea met secretly on Wednesday to discuss recent border altercations that involved gun fire, a South Korean opposition lawmaker and news reports said.

North Korea's military fired shots on Friday aiming at balloons sent by a private activist group from the South carrying leaflets with messages critical of North Korean leader Kim Jong Un, with some of the bullets landing in the South.

South Korea's military fired back in the incident that did not escalate or result in casualties.

The military officials met at the Panmunjom truce village that sits on the armed border separating the two Koreas, Park Jie-won, a senior opposition member of parliament said at a party meeting, according to a statement issued by the party.

Yonhap news agency also reported a meeting was held, citing an unnamed government source.

South Korea's Defense Ministry and the Unification Ministry, the main agency that deals with the North, declined to confirm whether such a meeting was held.

North Korea has reacted angrily to the practice by private South Korean groups of sending balloons with messages attacking its leadership, and has warned that planned talks between the two sides were at risk of cancellation because Seoul allowed the groups to proceed.

South Korea has said there was no legal justification to stop a private group's activities, but has urged the groups against sending the leaflets.

Earlier last week, the two sides exchanged gun fire after a North Korean patrol boat violated a sea border off the west coast. Pyongyang has refused to recognize the so-called Northern Limit Line that was drawn up after their 1950-53 civil war.

North Korea sent a high-level delegation to the South on Oct. 4 and agreed to resume dialogue that had been suspended in February, raising hopes of a breakthrough in relations.

South Korea was expected to propose a date for the talks to be held by early November to discuss holding reunions of families separated during the Korean War, and to discuss sanctions imposed after major military clashes in 2010 that killed soldiers and civilians in the South.

North Korea, heavily sanctioned by the United Nations for its missile and nuclear tests, is technically still at war with the South after the civil conflict ended in a truce, not a peace treaty.