About 20 graves at a Jewish cemetery in eastern France were marked with swastikas, the latest in a series of anti-Semitic acts in France that reportedly number up to a dozen a day, police said Saturday.

An obscene remark was scrawled on the wall of the Strasbourg-Cronenbourg cemetery and swastikas were painted on about 20 tombstones, according to police. The desecration was discovered Friday.

Three people, aged 19 and 20, were placed under investigation — a step short of being charged — Friday in connection with the April 5 discovery of a homemade bomb at the cemetery, according to judicial officials. Two others were placed under investigation on Monday.

France-Info radio reported Saturday that 10-12 anti-Semitic acts were being committed each day in France since Easter weekend. The information came from a report by French intelligence. The acts range from insults to physical attacks.

A member of a Jewish soccer team was injured last week during an attack on his team by a group of 15 hooded people wielding sticks and metal bars.

Synagogues, Jewish schools and cemeteries around the country have been targeted, often with firebombs, in recent weeks as fighting has escalated between Israelis and Palestinians. In the most serious case, a Marseille synagogue was burned to the ground on March 31.