Bricks were hurled though windows of Birmingham's Central Synagogue last Shabbat.
The attack occurred at around 10pm, after the conclusion of the Friday night service. The perpetrator was a man said to be in his 20s.
Police were called after the damage was discovered by the 80 community members arriving for the Shabbat morning service.
Shul president Geoffrey Clements reported: "The caretaker said there had been an incident where two ornate etched festival windows were smashed.
"The windows are irreplaceable. Each depicts a different festival and they were designed for the shul when it opened in the late 1960s."
Mr Clements added that if anti-shatter film had not been placed on the windows, in accordance with Community Security Trust guidelines, "the damage would have been much worse."
Sergeant Michael Richard from Edgbaston's neighbourhood police team said the attack was being treated as criminal damage rather than a hate crime, "following a similar incident in the vicinity on the same night.
"We believe that the windows of the synagogue will cost thousands of pounds to replace, so we understand how distressing this has been for the Jewish community."
The CTS's Mark Gardner said: "We'll advise on what can be done to replace the windows, look at the CCTV and see if anything more can be done to ensure this doesn't happen again."