The South Korean military found 30 more wooden-boxed landmines Monday on the islets near Ganghwa Island, bringing the total number of mines that appear to have drifted from North Korea over the last four days to 66.

“As of 4 p.m. we found 29 mine boxes from Gyodong islet and one from Boleum islet. Of them, six were just empty boxes,” said an official at the Joint Chiefs of Staff.

The military mobilized a total of 993 soldiers to search for the stray mines.

While it says it cannot verify whether the North has intentionally sent the mines to inflict damages on South Koreans, the military currently assumes that the mines drifted to the South due to the recent torrential rains.

“We understand that many wooden-boxed mines have been planted along the frontline areas,” said a JCS official.

The South Korean Army sent a message through a cross-border military hotline Sunday, urging the North to prevent the recurrence of similar accidents, the Ministry of National Defense said.

On Saturday, a 48-year-old man was killed and a 25-year-old man was injured after a mine explosion in a restricted area near the border with North Korea.

The finding of the mines comes after a rise in inter-Korean tensions following the March sinking of the corvette Cheonan. The South holds the North responsible for the incident that took the lives of 46 sailors. The North denies its culpability.

By Song Sang-ho (sshluck@heraldcorp.com)