BESLAN, September 3 (RIA Novosti) - Over 5,000 people attended a service on Thursday in Russia's North Caucasus town of Beslan to remember those who were killed in a school siege five years ago.

Chechen terrorists stormed Beslan's School No. 1 on September 1, 2004, the first day of the school year, herding teachers, parents and children into the gym and setting up explosives. 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.

They held a minute of silence after a bell in the courtyard of the school - left in ruins as a memorial to the dead - tolled at 1:05 p.m., the time of the first explosion. 335 balloons, one for each of the dead, were released into the sky.

The mourners then moved on to a cemetery for the victims of the siege, where the names of the dead were read out.

The Beslan school siege is the deadliest terrorist attack ever to take place in Russia and saw the largest number of child victims in any terrorist act anywhere in the world. Over 120 of the survivors were left disabled, including 70 children.

Disputes are still rife on the authorities' handling of the hostage crisis.

Mothers of Beslan, a support group of parents whose children were killed in the siege, lodged three complaints with the European Court of Human Rights on Wednesday accusing local authorities of negligence and failure to deter and investigate the tragedy.

Rights activists demanded an international probe into the hostage crisis last September, accusing the Russian authorities of bias in official investigations.