DETROIT - Ford says it will shut down 10 of its North American assembly plants for an extra week in January due to the slumping U.S. auto market.

Spokeswoman Angie Kozleski says the normal two-week holiday shutdown will be extended to Jan. 12 at all operating assembly plants except those in Claycomo, Mo., near Kansas City and the Dearborn, Mich., truck plant.

Those two plants will return to work as normal on Jan. 5. Both make the new F-150 pickup truck, while Claycomo also makes the Ford Escape and Mercury Mariner.

Ford will also extend the shutdown at some engine, transmission and parts stamping plants, or shut portions of them to match production cuts at the assembly plants.