Police officers leave a house with seized evidence in Berlin, Dec. 14, 2023. (Paul Zinken/picture alliance via Getty Images)

(JTA) — Police in three European countries arrested seven men they said were planning terror attacks against Jews and Jewish sites on Thursday.

Some of the men arrested were longtime Hamas members who began building a weapons cache in Berlin after Hamas’ Oct. 7 attack on Israel, according to German officials.

Three of the suspects were arrested in Germany, while one was arrested in Rotterdam, in the Netherlands. Police in Denmark arrested three other men, with Danish Prime Minister Mette Frederiksen saying the threat was “as serious as it gets.”

German officials described the suspects as “longstanding members of Hamas” who “have participated in Hamas operations abroad.” Hamas is considered a banned terror group across the European Union.

The men arrested by Germany were accused of building a weapons cache in Berlin, starting in October. The Guardian reported that the suspects have ties to Khalil Hamed al-Kharraz, the former second in command of Hamas’ military wing who was killed by Israeli bombing in Lebanon last month.

“It is of course – in relation to Israel and Gaza – completely unacceptable for someone to bring a conflict elsewhere in the world into Danish society,” Frederiksen said at an EU meeting in Brussels.

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Danish police said they would increase security for the near future at Jewish sites.

Shortly after Oct. 7, a Hamas official stirred global panic after urging action in “cities everywhere.” But even as countries around the world have dealt with threats to Jewish institutions since Oct. 7, most arrests have been described as lone-wolf cases, such as this week’s arrest of an Austrian teenager plotting to attack a Vienna synagogue.

Watchdogs have reported that antisemitic incidents have surged more than 300% in Germany and more than 800% in the Netherlands since the start of the Israel-Hamas war.

Israel’s intelligence agencies, Mossad and Shin Bet, jointly commended Danish police for their work. Their statement said police in Denmark had apprehended seven suspects, suggesting that the investigation that netted the German and Dutch arrests might have originated in Denmark.

“The Hamas terrorist organization has been working relentlessly and exhaustively to expand its lethal operations to Europe, and thereby constitute a threat to the domestic security of these countries,” the agencies said. “The Mossad and the ISA will continue to combine forces and capabilities with their partners in the country and around the world in order to thwart Hamas’s intentions and eliminate its capabilities.”

This article originally appeared on JTA.org.

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