Seoul , South Korea ( CNN ) -- North Korean and South Korean military units exchanged gunfire near their border Friday , South Korean authorities said . No casualties were reported . The exchange happened after North Korean forces fired two rounds from a 14.5 millimeter machine gun at a South Korean military guard post near the border town of Chorwon , South Korea , about 73 miles ( 118 km ) northeast of Seoul , according to an official at the Joint Chiefs of Staff . The South Korean unit responded with three `` warning shots '' from a .50-caliber machine gun and warned the North Korean guard post by loudspeaker to desist , the official said . The demilitarized zone at the location of the shooting is 1.3 kilometers ( 0.8 miles ) wide . Chorwon was the scene of heavy fighting during the 1950-53 Korean War . North Korea on Friday threatened to retaliate against its neighbor for shunning bilateral military talks . The gunfire exchange apparently wo n't cancel reunions of families separated by the Korean War , which ended in a truce but no formal peace treaty . The weeklong reunions begin Saturday at Mount Kumgang , the two countries ' joint mountain resort in the North . North Korea has requested record shipments of rice and fertilizer in exchange for concessions on the reunions , the South Korean Yonhap news agency reported earlier this week . While there are occasional shooting incidents across the demilitarized zones , the tensest flash point on the peninsula in recent years has been the disputed maritime border in the Yellow Sea . There were fatal naval clashes there in 1999 and 2002 . In March this year , the sinking of a South Korean vessel killed 26 in what a South Korean and international investigation team concluded was a North Korean torpedo attack . North Korea continues to deny involvement . The prickly relationship between the countries since the Korean War has had periodic conciliatory moves and flare-ups . Friday 's incident occurred two weeks before the G-20 summit in Seoul . The G-20 includes industrialized nations and developing economies , which focus on economic issues and economic policy coordination . Authorities said a total of 50,000 police and riot police will be deployed during the summit on November 11 and 12 , according to Yonhap . Journalist Andrew Salmon contributed to this report .
The incident was at the border of North Korea , South Korea . It reportedly occurred at a border post . The demilitarized zone at the location is not very wide .