Speaking ahead of the funerals in Tehran of diplomats killed by Taleban fighters in Afghanistan, Mr Kharrazi said that relations between the two countries were deteriorating.

"There is significant pressure on the Iranian authorities to resort to military means to avenge the crime," Mr Kharrazi said.

Mr Kharrazi told the Pakistani Minister, who arrived in Tehran on Thursday, that both Pakistan and the Taleban militia should take practical steps to avoid an escalation.

He also said that diplomatic means should be given priority in attempts to end the crisis with Afghanistan.

Pakistan tries to mediate

Iranian television reported that the Pakistani foreign minister would deliver a message from Prime Minister Nawaz Sharif to Iran's President Khatami.

The Pakistani minister was quoted as saying that his country was doing its utmost to secure the release of other Iranians held by the Taleban.

He also said Pakistan regarded its ties with Iran as important.

Pakistan is widely seen as the principal backer of the Taleban.

Fears of war

Tension has been rising between Iran and the Taleban since the killing of the diplomats after the Taleban captured the town of Mazar-i-Sharif from the Afghan opposition.

The Taleban now control nearly all of Afghanistan.

Iran has sent tens of thousands of troops to the border area with Afghanistan, and warned of conflict unless the killers of its diplomats are handed over.

The Taleban says it is hunting for the killers, whom it describes as renegade soldiers, and says they will be tried in Afghanistan once they have been caught.