Israeli Prime Minister Benjamin Netanyahu said that Iran should remain under biting sanctions until it halts all uranium enrichment, appearing to exceed UN demands on Tehran.

His remarks appeared aimed at stepping up pressure on Iran as it engages in revived international nuclear negotiations amid increased speculation in recent months that Israel may soon take military action to halt its nuclear drive.

"They have to stop all enrichment," Netanyahu told CNN in an interview in Jerusalem, adding that he would not accept Iran enriching uranium to even three percent, which is near the level required for peaceful atomic energy.

"After you stop all enrichment... you will get these (fuel) rods from another country that can allow you to use nuclear energy for peaceful purposes," he said.

Netanyahu said Iran must also "dismantle the underground bunker," apparently referring to the Fordo site near the holy city of Qom, where UN inspectors say it has begun enriching uranium to 20-percent purity.

When asked if he worried that his language might commit Israel to launching a military strike against Iran's nuclear facilities, Netanyahu replied: "I'm not worried what we look like. I'm worried about stopping this."

Israel's Chief-of-Staff Lieutenant General Benny Gantz told an Israeli newspaper in an interview published on Wednesday he does not believe Iran will take the decision to build a nuclear bomb.

Speaking to the left-leaning Haaretz newspaper, Gantz said Iran was going "step-by-step to the place where it will be able to decide if it wants to manufacture a nuclear bomb.

"It still hasn't decided yet whether to go the extra mile," he said, expressing a view also held by the administration of US President Barack Obama.

Iran has already developed the capacity to enrich uranium to 20 percent, which is used to create medical isotopes, but going "the extra mile" would mean working to enrich to 90 percent -- the level needed to make nuclear weapons.

"If the supreme religious leader Ayatollah Ali Khamenei wants, he will move forward towards acquiring a nuclear bomb, but the decision must first be taken," he said.

"In my opinion, he would be making a huge mistake if he does so, and I don't think he will want to go the extra mile," Gantz said.

"I think that the Iranian leadership is made up of very rational people."

Israel has long seen Iran as the greatest threat to its survival, both because of Tehran's nuclear program and because of its leaders' calls for the Jewish state to be wiped off the map.

Tehran has insisted its nuclear program is entirely peaceful and has claimed the right to enrich uranium for civilian purposes.

An Iranian envoy is scheduled to meet with representatives of the P+5 group, which includes the five permanent UN Security Council members and Germany, in Baghdad on May 23 for fresh talks aimed at resolving the nuclear impasse.