The global campaign of imposing sanctions against Iran has so far failed to halt Tehran's controversial nuclear drive, Israeli Prime Minister Benjamin Netanyahu said on Tuesday.
"The sanctions are painful, hard.. but will this bring about a halt or a retreat in the Iranian nuclear programme? Until now, it has not happened," Netanyahu told reporters in Jerusalem.
He said the Iranian regime is struggling financially but has strengthened its political grip following the recent parliamentary elections.
"The regime strengthened its grip in the recent elections, despite the sanctions," he said of the parliamentary elections which took place in Iran in early March.
"It has strengthened its political grip, it is struggling financially and it still hasn't turned back by even one millimetre from its nuclear programme.
"Will these difficulties cause the Iranian regime to stop its nuclear programme? Only time will tell. I can't tell you if it will happen. I know there is hardship but there still hasn't been a change."
Israel has said frequently it is keeping all options open for responding to Iran's nuclear programme, which it says is aimed at securing nuclear weapons, posing an existential threat to the Jewish state.
Although the United States and much of the West also believe Iran is seeking a militarised nuclear capability, they have called for time to allow biting sanctions to take effect.
So far, the UN Security Council has imposed four sets of sanctions on Tehran over its nuclear activities, while the US and Europe have also imposed their own raft of unilateral economic sanctions.
Iran has consistently denied that its nuclear programme is aimed at making atomic weapons.
But on Monday it said it would not be swayed from its nuclear "path" by sanctions, a week before it is due to hold key talks with world powers over the controversial drive.
Israel, the sole if undeclared nuclear power in the Middle East, and the United States have both threatened military action against Iran's nuclear facilities if diplomacy and sanctions fail to curb the Islamic Republic's nuclear ambitions.