"They must understand that such an attitude will only persuade us more to have nuclear technology," said top nuclear negotiator Ali Larijani, responding to widespread condemnation of comments by President Mahmoud Ahmadinjad.

Iran has been the focus of an international outcry after Ahmadinejad last week called for Israel to be "wiped off the map". The storm has also raised concerns over the country's bid to master sensitive nuclear fuel technology.

"There won't be a war. They do not have the means to go to war on two fronts," Larijani was quoted as saying by the student news agency ISNA in a reference to the continued hostilities faced by US-led forces in neighbouring Iraq.

"Iran is a hard target," insisted Larijani, who was addressing a seminar on nuclear energy.

"If they think they can limit us by oil sanctions or other sanctions, they are wrong. Oil sanctions will only increase the price of oil," he warned.

Iran says it only wants to develop nuclear power for electricity generation, but the United States and European Union fear Iran is using the fuel cycle as a means to acquire atomic weapons.