North Korea frequently released water from a dam near the inter-Korean border in July despite South Korea's request for prior notice, Seoul's unification ministry said Tuesday.

Some of the floodgates of the Hwanggang Dam were opened to discharge water on July 20, 24 and 27, without the North notifying the South of its release plan in advance, according to a report by US-based media outlet Radio Free Asia last week.

"The North was found to have frequently discharged water (from the dam) in July, including on those three dates, in a bid to adjust the water level," a ministry official told reporters on condition of anonymity.

The ministry earlier requested North Korea to give prior notice if it releases water from the Hwanggang Dam on concerns that Pyongyang's potential discharge of a large amount of water during the seasonal monsoon season could cause damage to border areas.

The official said the government is closely watching the situation, as there has been no serious damage so far in South Korean border regions.

"But it is very regrettable that North Korea has discharged water from the dam despite our repeated request," he added.

In October 2009, North Korea agreed to notify the South in advance when it plans to release water from the dam, following an accident that killed six South Koreans after the North discharged water from the dam without notice.

But last year, North Korea released water from the Hwanggang Dam without notifying Seoul, prompting the ministry to voice regret over the North's action. (Yonhap)