Updated

A Western official says the United States is considering deploying about 150 soldiers for military exercises to begin in Poland and Estonia in the next few weeks.

The exercises would follow Russia's buildup of forces near its border with Ukraine and its annexation last month of Ukraine's Crimean Peninsula. Defense Secretary Chuck Hagel said earlier this week that the U.S. is looking for ways to reassure its NATO allies of its strong commitment to collective defense.

The Western official says ground exercises in Poland and Estonia would last about two weeks but that such exercises would continue on a rotating basis off and on over time.

The official isn't authorized to discuss the plan by name because it hasn't been made final and requests anonymity.