Claim: In the Beslan school siege it is unknown how many children and teachers died.
Evidence: The Beslan school siege (also referred to as the Beslan school hostage crisis or Beslan massacre) started on September 1, 2004, lasted three days, involved the imprisonment of over 1,100 people as hostages (including 777 children), and ended with the deaths of either 331 or 334 people, more than half of which were children. 334 people (excluding terrorists) were killed, including 186 children. 
At that time The Washington Post stated that the death toll was 334, excluding terrorists. The City of Beslan has a death toll of 335 stated on its website. Children aged 1 to 17 186 Teachers and school staff 17 Total 333