"Iran will not stop unless it sees clear determination by the democratic countries of the world and a clear red line," Netanyahu told the Canadian television channel.

"The sooner we establish one, the greater the chances that there won't be a need for other types of action," he said.

Over the past week, the Israeli leader has repeatedly driven home the need to draw a "clear red line" for Iran and make clear the consequences of crossing it, in what was widely interpreted as a criticism of Washington.

"We're discussing it right now with the United States," Netanyahu said, without saying what would constitute a red line.

"The issue is not merely the sanctions or the steps that could be enhanced to put pressure on Iran. It's also a clear delineation of a line which Iran cannot cross in its pursuit of the development of nuclear weapons capability," he said.

"If Iran saw that, there's a chance... they might pause before they cross that line."

Last week, Netanyahu insisted that red lines were necessary in order to avoid war. "The greater the resolve and the clearer the red line, the less likely we'll have conflict," he said on September 3.

In recent weeks, tensions with Washington have risen sharply over reports Israel was planning to attack Iran's nuclear facilities without White House approval.

Israel, the Middle East's sole, if undeclared, nuclear power, says a nuclear Iran would constitute an existential threat for the Jewish state and has refused to rule out a military strike to prevent it from gaining such a capability.

Washington and much of the West also believe Iran is seeking a weapons capability under the guise of a civilian nuclear programme, a charge which Tehran denies.