North and South Korea have presented their cases to the UN in a dispute over the sinking of a Southern warship.

朝鲜韩国分别就韩国战舰沉没事件向联合国陈述各自观点。

The warship row has intensified tensions on the Korean peninsula
Seoul asked the UN to take "timely and appropriate measures", blaming Pyongyang for March's sinking of the Cheonan, which killed 46 sailors.

But the North denied involvement and said it was the victim.

After hearing separate submissions（意见书） from both sides, UN officials said they had "grave concern（严重关切） " over the issue and needed to debate it further.

"The Security Council makes a strong call to the parties to refrain from（避免） any act that could escalate（升级） tensions in the region," the council said in a statement.

The BBC's Barbara Plett, at the UN headquarters in New York, says the South Koreans presented evidence, including a Powerpoint presentation, which they said showed their warship was sunk by a North Korean torpedo（鱼雷，水雷） .

"We hope that on the basis of this finding the Security Council will take timely and appropriate measures against North Korea," said South Korean delegate Yoon Duk-yong.

UN diplomats said the North Koreans demanded an opportunity to visit the site of the explosion, and once again rejected South Korea's allegations as forgery（伪造） and fraud.

"We are just a victim, we would like to make our position clear here, we will inform our position, concerning that issue," said Pak Tok-hun, the North's deputy UN ambassador.

Our correspondent says there is still no agreement on what to do.

Security Council members China - North Korea's strongest ally - and Russia have not yet commented on the investigation.

The warship row has left inter-Korean relations highly tense. Seoul has suspended inter-Korean trade and Pyongyang responded by cutting all ties.