Tribal members in Colorado marked the 150th anniversary of one of the worst massacres in U.S. history Wednesday by paying tribute at an old Denver cemetery to two U.S. Army officers who refused to participate in it.

On Nov. 29, 1864, Capt. Silas Soule and Lt. Joseph Cramer declined orders to open fire on Cheyenne and Arapahoe men, women, and children.

About 200 people were killed in a dry riverbed in what became known as the Sand Creek massacre.

On Wednesday, about 70 tribal members took part in a sunrise blessing at Riverside Cemetery before completing an annual healing run to the state Capitol, where Gov. John Hickenlooper apologized on behalf of the state for the massacre. - AP