Kabul, Afghanistan (CNN) - More than two dozen American troops are believed to have died in the deadly helicopter crash in eastern Afghanistan on Saturday, a U.S. military official told CNN.

President Barack Obama issued a statement expressing his condolences to the families of the troops.

"My thoughts and prayers go out to the families and loved ones of the Americans who were lost earlier today in Afghanistan," Obama said. "We also mourn the Afghans who died alongside our troops in pursuit of a more peaceful and hopeful future for their country."