Japan may slip from its position as the world's third-largest economy, following the United States and the European Union, by 2015, according to a U.S. government report released Monday.

The report by the National Intelligence Council says Japan's economic performance in the next 15 years will be stronger than in the 1990s but its relative importance in the global economy will decrease.

"In the view of many experts, Japan will have difficulty maintaining its current position as the world's third-largest economy by 2015," the report says.

The NIC's report questions Japan's preparedness to carry out the structural reforms needed to resume robust economic growth, saying, "Tokyo has so far not shown a willingness to carry through the painful economic reforms necessary to slow the erosion of its leadership role in Asia."