Officials say first lady Michelle Obama will open a three-day tour focusing on youth fitness with an event in Des Moines, Iowa, next month.

The Feb. 9 event in Iowa marks the second anniversary of her Let's Move initiative, which promotes physical fitness and healthy eating for children.

The first lady's press secretary Hannah August says Obama picked Iowa to launch the tour because of the Healthiest State program. The public-private initiative backed by Gov. Terry Branstad and others says its goal is making Iowa the nation's healthiest state by 2016.

August says thousands of children are expected to join at an event featuring Obama as well as Branstad and Tom Vilsack, the U.S. agriculture secretary and former Iowa governor.

August didn't name other cities on the tour.