Iran is to dig 320,000 graves in border districts to allow for the burial of enemy soldiers in the event of any attack on its territory, a top commander said on Sunday.

"In implementation of the Geneva Conventions... the necessary measures are being taken to provide for the burial of enemy soldiers," the Mehr news agency quoted General Mir-Faisal Bagherzadeh as saying.

"We have plans to dig 15,000 to 20,000 graves in each of the border provinces or a total of 320,000," the general said, some of them mass graves if necessary.

Bagherzadeh said Iran was keen to "reduce the suffering of the families of the fallen in any attack against our country... and prevent any repetition of the long and bitter experience of the Vietnam War."

His comments came as the United States continued to refuse to rule out an eventual resort to force against Iran over its contested nuclear programme, which the West fears is cover for a drive to build an atomic weapon.

They also came as Israeli officials spoke of their determination to prevent Iran developing a nuclear capability at all costs.

A former head of Israel's Mossad foreign intelligence agency said in comments published on Sunday that the Jewish state had one year to destroy Iran's nuclear programme or face the risk of coming under nuclear attack.

Shabtai Shavit told a London weekly that the "worst-case scenario" was that Tehran would have a nuclear weapon within "somewhere around a year".

"The time that is left to be ready is getting shorter all the time," he told the Sunday Telegraph.

Israel is the only, if undeclared, nuclear armed power in the Middle East.