Middle East Correspondent, James Muir: "These exercises will aggravate growing tension between the countries"

More than 70,000 soldiers from the elite Revolutionary Guards have been testing their latest weapons and equipment.

Reports say tanks and aircraft are also taking part in the manoeuvres in an area 50km from the Afghan border.

An Iranian foreign ministry spokesman told the BBC the exercises were linked to the disappearance of 11 diplomats in northern Afghanistan, who Iran says were captured by the Taleban.

Diplomats 'may be dead'

The Taleban leader, Mullah Mohaamad Omar, said on Monday the Iranians may have been killed by Taleban soldiers acting without their leadership's knowledge.

Iranian affairs reporter, Sadeq Saba, reports

The Iranian foreign ministry spokesman dismissed the statement and emphasised that Iran held the Taleban responsible for their safety.

He said it was Iran's right to rescue the diplomats if the Taleban did not release them immediately.

The aim of the military exercises, he said, was to make preparations in case there was a need for military options.

Tension escalates

The commander of the Guards, Major-General Yahya Rahim Safavi, told Tehran radio that Iran would not tolerate any insecurity in its borders with Afghanistan.

He said his troops would simulate attacks deep into enemy territory, but denied that Iran was seeking confrontation.