At the same time, Iranian naval forces were added to the manoeuvres and a commander spoke of being pushed towards war. Seventy thousand Revolutionary Guards, including paratroopers and commandos, have been in the border region since last week. Within days there will be 200,000 Iranian troops and 25,000 Taliban fighters facing each other across the border. Both sides have deployed tanks, artillery and rocket launchers.
The manoeuvres contrasted with a burst of pacific rhetoric from Tehran, where the Foreign Minister, Kamal Kharrazi, said diplomatic approaches should be given a last chance before taking military action. He said Tehran had mobilised "all its efforts" at regional and international levels to "ensure our interests" and had had some results. Shia Muslim Iran has shunned the extremist Sunni Taliban since it emerged four years ago. Tehran accuses it of being a puppet of Pakistan and the US, saying they want to use the Taliban to curtail Iran's influence.
Iran also fears the Taliban is waging a campaign to wipe out the Shia minority in Afghanistan. After the militia captured the province of Bamian, in central Afghanistan, on Sunday, Iran's leaders urged Shias there to "rely on God and resist the beasts."
However, moderates close to President Mohammad Khatami are less enthusiastic about a conflict. They have warned against getting involved in a "quagmire" in Afghanistan similar to the one the former Soviet Union found itself in when it imposed a pro-Soviet regime on the mountainous country in the 1970s.
"A direct clash is not in our interest, said the Qods newspaper, in Khorasan province, bordering Afghanistan.
"Though we can send a squadron of jets to blast Mullah Omar [the Taliban leader] in his stronghold in Kandahar," it added.
Others have suggested Iran should set up a militia of Afghan refugees, whose number is estimated at several million.
The public mood in Iran remains opposed to a war with Afghanistan, as people still have vivid memories of the 1980-1988 war against Iraq, when 300,000 Iranians were killed and 500,000 wounded.
Even so, Iran is most likely to use to some kind of forceful measures to punish the Taliban. The National Security Council, the top political and military decision-making body, has been exploring military options against the militia for several days. Iran says it reserves the right under UN charters forcibly to respond to Afghan aggression.
Earlier this week Iran's supreme leader, Ayatollah Ali Khamenei, told his troops to be prepared for "speedy and timely" action. Yesterday senior officers of the Revolutionary Guards, Iran's elite corps, said they were ready to fulfil any order their leaders gave.
The crisis was precipitated by the killing of 10 diplomats and a journalist by the Taliban when they seized the northern city of Mazar-e-Sharif last month. Though the Taliban handed over seven bodies on Sunday, neither side has softened its stance. Iran revealed yesterday that two other diplomats thought to have been killed had escaped.Reuse content