Mostly senior officers were killed. The Vympel unit lost seven officers and the Alpha unit lost three. According to the spokesman, Vympel unit had not lost so many men since it was created.
A FSB spokesman announced on Monday in Vladikavkaz that the burial of the officers would take place on Wednesday.
The spokesman said that FSB special forces suffered such heavy losses because the hostage rescue operation began spontaneously, when the roof of the school's gymnasium collapsed.
When the special forces entered the gym, they saw a mass of bodies, both dead and alive.
"The officers started to take the living out of the school building," the spokesman said.
The terrorists, who were on the upper floors in prepared positions, began to shoot the escaping hostages and the officers and civilians who were rescuing them. The FSB special forces shielded the children from the bullets with their bodies.
"I understand very well, the feelings of the officers and soldiers from the Vympel and Alpha units," the spokesman said. "They acted in the first place as fathers, brothers and sons, saving the children at the cost of their own lives."
One of the FSB officers, who carried a small girl away from the terrorists' fire, was wounded in the head and only came out of a coma on Monday.
"We hope he will recover," the spokesman said.
Other wounded special forces officers were mostly wounded on their extremities, but there are also more serious wounds, the spokesman said.
When visiting the scene of the tragedy on September 4, President Putin said that special services had sustained great losses.
"The events developed quickly and unexpectedly. The special services members behaved especially bravely," Mr. Putin said.
