United Nations (CNN) -- North Korea on Tuesday rejected international findings that it sank a South Korean ship, warning at the United Nations the dispute could lead to war.

"A war may break out any time," Ambassador Sin Son Ho said, accusing South Korea of "fabricating" the results of the investigation into the sinking of the Cheonan.

The loss of the ship and 46 sailors in March raised tensions on the Korean Peninsula.

North and South Korea presented their cases to the United Nations on Monday, and South Korea then urged the Security Council to take "timely and appropriate measures."

North Korea's envoy responded harshly Tuesday.

"If the Security Council releases any documents against us, condemning or pressuring us ... then myself as diplomat, I can do nothing. ... The follow-up measures will be carried out by our military forces," he said.

Why are the two Koreas so hostile?

U.N. Security Council President Claude Heller said Monday that the U.N. body is "gravely concerned" about the latest tensions.

Heller said the council is concerned over the potential "impact on peace and stability on the Korean peninsula" as a result of the March 26 sinking of the Cheonan in disputed waters.

"We presented and explained to [the council] the evidence that the Cheonan was sunk by a torpedo, which was made in North Korea, and launching was also done by a North Korean ... submarine," said Yoon Duk-yong, a science and physics professor serving as a civilian expert on the South Korean panel.

Yoon said the findings were based on evidence recovered after the sinking, including an intact piece of the torpedo with propellers, steering plates and a motor.

"We hope that on the basis of these findings," he said, "the Security Council will take timely and appropriate measures against the provocation of North Korea against the naval ship of the Republic of Korea."

But North Korea's ambassador disputed the international findings, comparing them to "some kind of fiction in Aesop's Fables."

"The 'investigation result' is a complete fabrication from A to Z," he said.

The council is calling on both sides "to refrain from any act that could escalate tensions in the region," Heller said.

The two-hour meeting was held behind closed doors Monday afternoon and was also attended by U.S., Australian, British, Swedish and Canadian scientific experts who had participated in the investigation.

The Japanese ambassador to the United Nations made brief remarks following the two nations' presentations, saying "there is no other explanation" than that the South Korean ship was sunk by a North Korean torpedo.

"I think the council should react in a decisive manner, but at the same time try to avoid any act which may provoke" a retaliatory attack, Ambassador Yukio Takasu said.

North Korea repeatedly has denied any responsibility in the sinking.

Heller said a decision has not yet been made on how to respond to the incident.

"The Security Council will continue its consultations," he said.