SEOUL, South Korea - May 16, 2010 - South Korea's navy has fired warning shots at North Korean patrol boats that strayed across the sea border between the two countries.
The incident occurred when two North Korean vessels violated the Northern Limit Line border and ventured into South Korean waters, the office of South Korea's Joint Chiefs of Staff said.
He added that the North Korean ships then retreated without responding to the fire and there were no casualties.
"Two patrol boats crossed on two separate occasions and warning shots were fired," a spokesman said.
The area was the scene of deadly naval clashes in 1999 and 2002, and of a firefight last November, which set a North Korean patrol boat ablaze. The North has never recognised the border, since it was drawn up by the United Nations after the Korean War.
The latest encounter comes amid rising tensions between the two countries in the wake of the sinking of a South Korean warship on March 26 in the same region.
In South Korea, there are increasing suspicions that a North Korean torpedo was responsible for the destruction of the ship, with the loss of 46 lives. Three-way talks between South Korea, China and Japan are taking place this weekend and the sinking of the ship has been discussed.
Yang Jiechi, China's Foreign minister, said China expressed its "condolences for the loss of many lives due to the sinking of the navy ship Cheonan".
China is North Korea's biggest ally, and Kim Jong-il, the leader of the rogue state, recently met with Chinese leaders in Beijing. Mr Yang also called for "calm and restraint" when dealing with the sinking of the ship.
