President Barack Obama is offering condolences to the families of more than a dozen Afghans who were allegedly shot by a U.S. soldier on Sunday.
In a statement released by the White House, Obama called the attack "tragic and shocking."
He also vowed "to get the facts as quickly as possible and to hold accountable anyone responsible."
Afghan officials reported that 16 people were killed, including nine children and three women, in the southern Kandahar province.
Defense Secretary Leon Panetta said he told Afghan President Hamid Karzai on Sunday that a suspect was in custody and that "we will bring those responsible to justice."