VLADIKAVKAZ, September 2 (RIA Novosti) - A requiem service for the more than 300 people killed when Chechen separatists seized a school in Russia's North Caucasus town of Beslan will be held on Thursday.

Terrorists stormed into Beslan's School No. 1 on September 1, 2004, herding teachers, parents and children into the gymnasium and setting up explosive devices. September 1 is traditionally the first day of the new school year in Russia.

Of the 1,200 people taken hostage, 335, including 186 children, lost their lives as the siege came to its bloody conclusion three days later.

The remembrance ceremony begins at 11:00 a.m. [07:00 GMT] in the courtyard of the school, now in ruins but left standing as a memorial to the dead.

At 1:05 p.m., the time of the first explosion and the beginning of the end of the siege, 335 balloons, one for each of the dead, will be released into the sky.

The mourners will then move on to a cemetery for the victims of the siege, where the names of the dead will be read.

The Beslan school siege is the deadliest terrorist attack ever to take place in Russia and saw the largest amount of child victims in any terrorist act anywhere in the world.

Over 120 of the survivors were left disabled, including 70 children.