Iranian Foreign Minister Kamal Kharrazi launched the blistering attack on Monday in response to accusations that Tehran is seeking to build atomic weapons.
Israel had claimed that it was Iran which posed a huge threat.
“Israel wants to justify its nuclear arsenal. They want to justify that they are under threat when the source of the threat is Israeli capabilities,” Kharrazi told a news conference in South Africa, where he is holding diplomatic meetings.
The minister also denied any nuclear weapons programme and stressed atomic power in Iran was for the production of electricity.
Kharrazi said Tehran had embarked on a nuclear programme as it was currently exporting most of its 3.8 million barrel-per-day oil output.
Iran also realised the need to develop alternative sources of energy in the face of declining oil reserves and a rapidly growing population.
“We don't find the development of nuclear weapons increases security. Contrary to that, we find it to be a threat to national security," Kharrazi concluded.
Earlier, Israeli Foreign Minister Silvan Shalom told reporters in Brussels on Monday that Tehran was attempting to build a nuclear weapon and would pose a threat to the world unless it was stopped.
"Iran now is trying to do everything to have a nuclear weapon and that is threatening not only the Middle East, it is threatening Europe, the southern part of Russia," he said.
Shalom, speaking to reporters after meeting his counterparts from the European Union, said Tehran was enriching uranium and refusing to accept tougher inspections of its nuclear programme.
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Iran confirmed on Sunday its Revolutionary Guards had been armed with a new medium-range missile, which analysts say could hit Israel - a close US ally – or the numerous US bases in Afghanistan, Iraq, Kuwait, Bahrain, Qatar, Oman and Saudi Arabia.
EU foreign ministers last month demanded Iran accept even tougher inspections of its nuclear programme, and linked compliance to progress on a pending trade deal.
It was the most serious warning the EU had sent Tehran since they began negotiating a trade and cooperation agreement late last year.
But Israel has never signed the Non-Proliferation Treaty and has never acknowledged possessing nuclear weapons.
Tel Aviv also refuses to let the International Atomic Energy Agency inspect its nuclear equipment, in breech of Security Council Resolution 487.
Defence experts believe Israel possesses 100 to 200 nuclear heads that can be launched by ballistic missiles.