Tel Aviv, Dec. 29 -- The Israeli government revealed Sunday evening that, in what it called "a blow to Hamas' infrastructure in Europe," Israeli assistance with information and evidence for law enforcement in Italy led to the investigation and arrests of Muhammad Hanun, the Hamas leader in that country, and six other senior people in the organization there, including a senior figure in Hamas's leadership in Europe and a member of Hamas's leadership on the continent.

A joint task force of the Economic Counterterrorism Headquarters (ECT) in Israel's Ministry of Defence, the Intelligence/CEO Division of the Israel Police, the IDF (Israel Defence Forces) Intelligence Division, and the Shin Bet (Israel's anti-terror General Security Service),...