Senior U.S. officials said the analysis of information collected by the 16 U.S. intelligence agencies is "based on their sense of the political dynamics there rather than hard evidence," The New York Times reported.
"We can't say it is established fact. But there is very little doubt, based on what we know about the current state of the North Korean leadership and the military," a senior U.S. official told the Times.
On Monday South Korean President Lee Myung-bak is expected to ask the U.N. Security Council to condemn the attack, which killed 46 sailors.
Rosie O'Donnell unveils nearly 50-pound weight loss
Members of Congress to keep receiving porn magazine