RUSSIA said yesterday the gas used in its disastrous Moscow theatre raid was based on Fentanyl, a fast-acting opiate with many medical applications.

Russia’s top health official today revealed that the gas used in the special forces storming of a Moscow theatre held by dozens of gunmen was based on Fentanyl, a fast-acting opiate that has many medical applications.

Two more hostages, freed from the Moscow theatre siege by Russian troops, died in hospital overnight from the gas used to incapacitate them and their captors.