"We're in the same boat," he told Israeli army radio in an interview.
"The world finds itself at the moment in a third world war, or as it has been called, 'a clash of civilisations'. We must face it together."
"We cooperate with Belgium and other European countries," he added. "We are on the same side, with shared values and interests."
The jihadist Islamic State group has claimed responsibility for Tuesday's attacks on the airport and a metro station in the Belgian capital that killed 31 people and wounded another 300.
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"If in Belgium they continue to eat chocolate, enjoy life and parade as great liberals and democrats while not taking account of the fact that some of the Muslims who are there are organising acts of terror, they will not be able to fight against them," Yisrael Katz told public radio.
Yaalon responded today by saying: "I would suggest not giving advice in public. And I'd be happy to eat dark Belgian chocolate."
Israeli former president and Nobel Peace Prize laureate Shimon Peres in Paris today asked local religious leaders to give their communities a message of peace.
"There is no God in the heavens that permits terrorism, there is no God willing to murder the innocent -- babies, children, here in Europe, in the Middle East or the rest of the world.