The Asiana Airlines flight carrying 119 people from the Chinese city of Chengdu was undamaged in the incident around dawn Friday, the airline said. No one on board was hurt or aware of the shooting, and the South Korean Marine Corps informed the airline of it later in the day, it said.

The incident highlights how persistent tensions between the two Koreas create the chance of dangerous miscalculation. The Korean peninsula has remained in a technical state of conflict since the Korean War ended in a truce in 1953, and a peace treaty has never been signed.

"The Marine Corps did fire, but they misidentified the plane," Asiana spokesman Jason Kim said. "The plane did not suffer any damage and it landed safely."

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, Yonhap news agency reported, citing a military source it did not identify. The jet was flying out of range of the rifle fire, the report said.

The airport is about 25 miles (40 kilometers) south of the inter-Korean border. Gyodong island is north of the airport and closer to the border.

About 600 civilian aircraft fly near the island every day, South Korea’s YTN television reported.

Yonhap quoted its source as saying the marines claimed the plane was flying off course. However, an official with the Seoul Regional Aviation Administration said that radar showed the aircraft was not off course.

South Korea’s Defense Ministry and Marine Corps could not be reached for comment Saturday.

The incident comes amid simmering tensions between the Koreas which spiked last year after the sinking of a South Korean navy ship in March 2010 that killed 46 sailors. South Korea blamed North Korea, which denied involvement. Then in November, North Korean artillery attacked a front-line South Korean island, killing four people.

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

North Korea has demanded the immediate repatriation of all nine people. It 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.

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Associated Press writers So Yeon Kwon and Hyung-jin Kim contributed to this report.