Russia has started cooperating with Azerbaijan in investigating the crash of an Embraer 190 aircraft. Officials from four countries will conduct a comprehensive investigation into the cause of the crash,

Azerbaijani President Ilham Aliyev on Sunday demanded that Russia admit that it fired at an Azerbaijan Airlines passenger jet before it crashed, accusing Moscow of initially trying to cover up the cause of the fatal disaster.

Two U.S. military officials told NBC News that they had intelligence indicating that Russians may have misidentified the plane and shot it down.

The probe into the Azerbaijan Airlines crash in Kazakhstan is examining the conduct of air traffic controllers after the aircraft encountered difficulty, a source said.

Azerbaijan’s President Ilham Aliyev has accused Russia of accidentally shooting down an airliner on Christmas Day in a disaster that killed 38 people, and covering up the cause.

"We can clearly say today that the plane was shot down by Russia," President Ilham Aliyev said in a televised statement