The number of threats against Swedish Jews has doubled since the Paris attacks and the killing of four people in a kosher supermarket, a representative said Thursday.

"The threats have at least doubled in Sweden," Lena Posner-Koeroesi of the Council of Jewish Communities told AFP.

Security has been increased around Jewish institutions, particularly in the capital Stockholm, police spokesman Lars Bystroem said.

Sweden has previously drawn international criticism for not taking threats to its Jewish community seriously.

"Saepo (the Swedish security service) and the police believe that we must have more protection and they are usually scrupulous in deploying their resources," Posner-Koeroesi said.

"They show a good understanding of our situation. That is important because members of the community are worried," she added.

According to the Council of Jewish Communities in Sweden, half of the country's 20,000 Jews live in Stockholm.