Marines fired rifles at a South Korean civilian jetliner as it was descending to land after mistaking it for a North Korean military aircraft, an airline official and a news report said Saturday.

The incident took place at dawn Friday, Yonhap news agency reported, citing a military source it did not identify. The Asiana Airlines jet carrying about 119 people was undamaged and no one was hurt.

The incident highlights how persistent tensions near the heavily armed inter-Korean border pose the possibility for dangerous miscalculation. The Korean peninsula has remained in a technical state of conflict since the Korean War ended in a truce in 1953. A peace treaty has never been signed.

South Korea's Defense Ministry and civil aviation officials could not immediately be reached for comment on the Yonhap report.

An Asiana official reached by telephone confirmed that marines fired small weapons at one of the airline's planes coming from China and that there was no damage. The official, who gave his surname as Bae, referred further comment to an airline spokesman, who could not immediately be reached.

Two marine guards stationed on Gyodong island near the border fired rifle rounds at the flight as it approached Incheon International Airport west of Seoul, mistaking it for a North Korean military plane, the Yonhap report said. The jet was flying out of range of the rifles and avoided damage, it said.

The airport is located about 25 miles (40 kilometers) south of the inter-Korean border.

Yonhap quoted its source as saying the marines claimed the plane was flying off course. Bae, the Asiana official, described the plane's route as normal.

News of the incident comes as South Korea on Friday refused to send back a group of North Koreans who crossed into southern waters by boat last weekend, saying all nine have expressed the desire to defect.

North Korea has demanded the immediate repatriation of all nine people who landed on a South Korean-held island last Saturday aboard two small boats. Pyongyang warned Thursday that failure to send them back would aggravate ties between the two Koreas.

North Korea threatened earlier this month to retaliate for the South Korean military's use of photos of leader Kim Jong Il's family for shooting practice.

Seoul also blames Pyongyang for two deadly attacks that killed 50 South Koreans last year. U.S.-made missiles capable of striking Pyongyang were deployed to South Korean sites near the Demilitarized Zone earlier this year, South Korean media reports said. South Korea's Joint Chiefs of Staff declined to confirm the reports.