In a statement in the name of the presidency of the 25-nation EU, Dutch Foreign Minister Bernard Bot on Friday said all countries should work together to prevent such tragedies.
"But we also would like to know from the Russian authorities how this tragedy could have happened," he said.
Reports suggest more than 200 people were killed when the siege of a southern Russian school ended in a shootout between the gunmen holding hostages and security forces.
Around 700 more were reported to be in hospital.
EU ministers avoided direct criticism of Moscow’s handling of the hostage crisis and expressed sympathy with the Russian people and government.
British Foreign Secretary Jack Straw said “terrorists” were to blame for the death toll and declined to comment when asked whether Russian authorities had bungled the chaotic rescue bid.
"I know that from President Vladimir Putin downwards, there was a complete commitment by the Russian government to do everything they could to save the life of the innocents," Straw said.