Israeli Defense Minister Ehud Barak Saturday, Feb 18, called on the world to tighten sanctions on Iran before the country enters a "zone of immunity" against a physical attack to stop its nuclear program, AFP reported.

"We have to accelerate the pace of imposing sanctions," he told a news conference in Tokyo.

The world must force the Iranians to ask themselves, "Are we ready to pay the price of isolation by most, if not all, of the world or should we decide to stop the nuclear effort?" he said.

"The world should ratchet up the sanctions before the Iranians fully enter this immunity zone," Barak said.

Barak, also Israel's deputy prime minister, has often used the phrase "zone of immunity" to mean a point where Tehran's nuclear program becomes invulnerable to physical attack.