Former U.S. Federal Reserve Chairman Alan Greenspan warned Monday that the American economy might slip into recession by year's end.

He said the U.S. economy has been expanding since 2001 and that there are signs the current economic cycle is coming to an end.

"When you get this far away from a recession invariably forces build up for the next recession, and indeed we are beginning to see that sign," Greenspan said via satellite link to a business conference in Hong Kong. "For example in the U.S., profit margins ... have begun to stabilize, which is an early sign we are in the later stages of a cycle."

"While, yes, it is possible we can get a recession in the latter months of 2007, most forecasters are not making that judgment and indeed are projecting forward into 2008 ... with some slowdown," he said.

The U.S. economy grew at a surprisingly strong 3.5 percent rate in the fourth quarter of 2006, up from a 2 percent rate in the third quarter. A survey released Monday by the National Association for Business Economics showed that experts predict economic growth of 2.7 percent this year, the slowest rate since a 1.6 percent rise in 2002.

Greenspan also said he has seen no economic spillover effects from the slowdown in the U.S. housing market.

"We are now well into the contraction period and so far we have not had any major, significant spillover effects on the American economy from the contraction in housing," he said.