Herzlia, Israel  - Diplomatic efforts to persuade Iran to abandon its nuclear programme must be accompanied by a clear timeline, after which harsh sanctions could be imposed, accompanied by a willingness to act, Israeli Defence Minister Ehud Barak said Tuesday.

He told an international conference in Herzlia, north of Tel Aviv, that all options regarding Iran were on the table. "Beyond that I will say nothing," he added.

Israel regards Iran as its biggest existential threat, given Tehran's nuclear programme and repeated statements by President Mahmoud Ahmadinejad and other Iranian leaders that the Jewish state should be erased off the map.

Israeli officials also see Iran as being the prime sponsor of Islamic fundamentalist organizations dedicated to destroying Israel, such as the Lebanese Hezbollah movement and Palestinian groups such as the Islamic Jihad and Hamas.

Barak said Israel would never sign any agreement with Hamas, which advocates replacing Israel with an Islamic state in all of historic Palestine.

"We will destroy and smash Hamas," he said, and added that the group had been deal a severe blow by the recent Israeli offensive against it and other militias in the Gaza Strip.

He warned that if Hamas continued to fire rockets at Israel, "we must respond and we are repsonding."

Barak, running at the head of the Israel Labour Party in next week's parliamentary elections, said a two-state solution - an Israeli and Palestinian state living side by side - was the only solution to the Israel-Palestinian imbroglio. dpa