Windows have been smashed on a synagogue in north Belfast.
Police said a window was smashed some time on Friday night or Saturday morning.
A replacement window was then smashed on Saturday afternoon or evening. Police are treating it as a religious hate crime.
They have appealed for anyone who witnessed the attacks or has any information about them to contact them on the non-emergency 101 number.
Rabbi David Singer said the Jewish community had been left shocked by the attack.
He said: "I think across the community, first of all, it's very sad that it happened. I would imagine that there's a certain amount of anger that it could happen, but angry in the sense of frustration, not angry in the sense that they'd want to do anything about it.
"Certainly, it's very sad and very disturbing that Belfast would show its face like this."
The Ulster Unionist leader Mike Nesbitt said it was "totally unacceptable" for places of worship to be targeted.
"The Jewish community have been valuable members of our society for many years," he said.
"We offered refuge during the Second World War to many fleeing the Holocaust and it is abhorrent that the synagogue has been the target of this hate crime."
Nigel Dodds, DUP, called the attacks "disgraceful and despicable".
"Those who have such hatred in their hearts to carry out this attack must be condemned. The Jewish community are a long established part of Belfast and have a rich history in the city. I trust the police will be able to apprehend those responsible for this latest act of hatred," he said.
Sinn Féin MLA Gerry Kelly said: "There can be no place for attacks on any place of worship, regardless of the religion or denomination.
"The local Jewish community makes a valuable contribution to our society and there is no justification for hate crimes.
"If anyone has any information on these attacks then they should contact the PSNI."
Alban Maginness, SDLP, said: "I totally condemn the attack on the north Belfast synagogue.
"Anti-semitism and race hate will not be tolerated by the people of Belfast.
"It is disgraceful that such a highly respected and law-abiding community and their place of worship should be attacked in this way."