WASHINGTON (AP) — The U.S. economy unexpectedly shrank from October through December, the first quarterly drop since 2009 and a reminder of the economy's vulnerability as automatic cuts in government spending loom.

The Commerce Department said the economy shrank at an annual rate of 0.1 percent mainly because companies restocked at a slower rate and the government slashed defense spending. Those trends partly reflected uncertainty late last year about the fiscal cliff, which Congress averted in a deal reached Jan. 1.

Economists say those factors could prove temporary, and the likelihood of another recession appears remote. Still, the sharp slowdown from the 3.1 percent annual growth rate in the July-September quarter, also driven by a drop in U.S. exports, raised concerns about 2013.