Paving slabs with swastikas scratched on them were thrown through the windows of a hall while a Hindu religious meeting was in progress.
No-one was injured in the racist attack, which happened late on Wednesday evening at Carnival Hall in Council Road in Basingstoke, Hampshire.
Hampshire Police has sent the two slabs for forensic analysis.
Ch Insp Chris Brown said: "Any racial or religious attacks on members of our community are treated very seriously."
He appealed for any witnesses to contact police.
"We have recently had several successful prosecutions for these kind of incidents and this shows that we will not tolerate such behaviour in the Basingstoke Area," he added.
The Swastika is an ancient Hindu symbol appropriated by the Nazis and the far right.