French President Francois Hollande called on Internet service providers to take action against the spread of anti-Semitism online.

During a visit to France's Holocaust Memorial on Tuesday, Hollande said Internet service providers cannot turn a blind eye to anti-Semitic theories that are disseminated on social networks. Other, he says, "they will be regarded as accomplices."

Concerns about anti-Semitism have risen after a kosher supermarket was targeted in the country's deadliest attacks in decades. Four Jewish people were among the 17 people killed by the three gunmen, who also died.

A report released Tuesday by a Jewish organization said the number of anti-Semitic acts doubled last year in France.