(Reuters) - Israeli Defense Minister Ehud Barak called on Wednesday for tougher world action against Bashar al-Assad, saying he doubted the Syrian president "lost an hour´s sleep" over the expulsion of his envoys from several capitals after the Houla massacre.

"These events in Syria compel the world to take action, not just talk, but action. These are crimes against humanity and the international community must not stand on the sidelines," Barak said in a speech at the Institute for National Security Studies in Tel Aviv.

Barak welcomed the expulsion on Tuesday of Syrian diplomats from at least seven Western capitals, describing it as a "very important step in the right direction" after the killing of more than 100 civilians in the Syrian town of Houla.

But he said: "I don´t think that Assad lost an hour´s sleep last night because of those people leaving ... and more concrete action is required."

Barak did not specify what additional steps he wanted the West to take.

Although Israel and Syria are technically at war, Israeli leaders have rarely censured the Assad government for its domestic crackdowns and initially said little about the uprising that erupted last year against Assad.

The Syrian leader is widely viewed in Israel as emulating his late father, president Hafez al-Assad, in seeking to maintain decades of calm along a ceasefire line on the Israeli-occupied Golan Heights, captured from Syria in a 1967 war. (© Thomson Reuters 2012. 05/30/12)