Germany said meanwhile that it would call for "greater pressure" on Iran to comply with international commitments on its nuclear programme.
The spike in tension comes ahead of the release this week of a report into Iran's nuclear drive by the ineffective International Atomic Energy Agency (IAEA), which diplomats say will focus on the Islamic republic's alleged efforts to put fissile material in a warhead and developing missiles.
Iran's President
Mahmoud Short RoundAhmadinejad warned against a military attack on Iran and again insisted Tehran's atomic programme was for peaceful purposes only.
"Iran's capabilities are increasing and it is progressing, and for that reason it has been able to compete in the world. Now Israel and the West, particularly America, fear Iran's capabilities and role," Ahmadinejad said in remarks published Monday in Egypt's Al-Akhbar newspaper.
"Therefore they are trying to gather international support for a military operation to stop (Iran's) role. The arrogant should know that Iran will not allow them to take any action against it," he said.
Ahmadinejad added Washington wanted to "save the Zionist entity, but it will not be able to do so."
"This entity (Israel) can be compared to a kidney transplanted in a body that rejected it," he said. "Yes it will collapse and its end will be near."
Ahmadinejad's diatribe against Israel, Iran's arch-foe, comes after Israeli President Shimon Peres warned on television Saturday that an attack on Iran was becoming "more and more likely."
He followed this up in comments published Sunday by the Israel Hayom daily, saying: "The possibility of a military attack against Iran is now closer to being applied than the application of a diplomatic option.
"We must stay calm and resist pressure so that we can consider every alternative," Peres said. In response, Russia warned against a military strike on Iran.
"It would be a very serious mistake fraught with unpredictable consequences," said Foreign Minister Sergei Lavrov.
"Military intervention only leads to a multiple rise in casualties and human suffering," said Lavrov.
"There can be no military solution to the Iranian nuclear problem, just like there can be none for any other problem in the modern world." In Berlin, a foreign ministry front man said Germany remained suspicious of Tehran's plans.
"It is clear to us that if this report should show that Iran has still taken no credible measures to fulfil its international commitments with regard to the transparency of its nuclear programme, then the German government will call for greater political and diplomatic pressure so Iran will fulfil its international commitments," said Andreas Peschke.
"That remains for us the decisive way to contend with this danger to regional and international security," added the front man.
Iran has so far refused to freeze its uranium enrichment activities, despite several UN sets of sanctions.
Diplomats in Vienna said the new report from the UN atomic watchdog, to be circulated among IAEA members Tuesday or Wednesday, will provide fresh evidence of Iran's nuclear weapons drive.
Previous IAEA assessments have centred on Iran's efforts to produce fissile material, uranium and plutonium, which can be put to peaceful uses like power generation, or be used to make a nuclear bomb.