国际英语新闻：DPRK warns S. Korea over warships entering its waters

The warning came as tension heightened between the north and south following the sinking of a South Korean warship near the maritime border.

South Korea released results of an investigation last Thursday, accusing the DPRK of sinking the Cheonan in a torpedo attack.

The DPRK's National Defense Commission immediately denied any wrong doing and offered to send inspectors to check the investigation results. The offer was rejected by the south.

South Korean President Lee Myung-bak on Monday demanded an apology from the DPRK and said his country would resort to measures of self defense in case of further military provocation by the north.

The Cheonan, a 1,200-ton warship with 104 crew members on board, sank on March 26 after an explosion. Only 58 sailors survived the incident.