MONSEY, N.Y.—A fire destroyed the synagogue and residence of a senior rabbi of an anti-Zionist, ultra-Orthodox Jewish group whose members attended an Iran-sponsored conference late last year that debated the occurrence of the Holocaust.

Police and fire investigators said the blaze last night in Monsey, about 35 miles north of New York City, was considered suspicious because the group, Neturei Karta, has been the target of threats, the Journal News reported on its Web site. Police would not confirm for The Associated Press that the blaze was considered suspicious.

No one was injured in the fire. The senior rabbi who lived at the location was in London.

Rabbi Yisroel Dovid of Neturei Karta said the group suspects arson because of previous threats.

"There's no question that the issue is to stifle the opposition to Zionism," he said by telephone early this morning.

Rabbi Moshe Beck, a senior rabbi for the group, lived on the top floor of the building, Dovid said. Beck is one of the group's more outspoken leaders.

"He's the backbone of much of the activity, so that's why he's supposedly been singled out," Dovid said.

In December, about five members of the group traveled to Tehran for a two-day conference convened to debate whether the Holocaust occurred. Some were photographed meeting with Iranian President Mahmoud Ahmadinejad, who has called the Holocaust a "myth" and criticized the existence of Israel.

The conference outraged many other Jewish groups.