The United Nations is forming a fact-finding mission to investigate the deaths of nine Iranian diplomats in northern Afghanistan.

UN Security Council President Hans Dahlgren of Sweden confirmed that, after discussions Thursday night, the 15-nation Council had agreed on the need for an “urgent investigation into these crimes”. The Council also called for a joint fact-finding mission involving Iran, Pakistan – an ally of Afghanistan’s ruling Taliban – and the United Nations, Dahlgren said.

The fate of other Iranians who were in northern Afghanistan in recent weeks remained a mystery. Dahlgren said that two Iranian diplomats were still missing, although the Taliban earlier this week returned five Iranian truck drivers seized during heavy fighting in the north back home as a sign of goodwill. (Some 40 Iranians in all are believed to be missing throughout Afghanistan.)

Tension increased, nevertheless, between Afghanistan’s Taliban – which controls more than 90 percent of the country – and Iran, which has backed several anti-Taliban forces. Iran was furious over the deaths of the nine diplomats, whose bodies were recovered from Afghanistan Thursday.

In recent days, Iran dispatched some 70,000 troops to the Afghan border for a “military exercise.” Some Council diplomats expressing growing concern that the troop build-up could lead to fighting between Teheran and the Taliban if the tensions over the murdered diplomats are not resolved.

Iran sharply condemned the murders of the nine diplomats, who were killed after the northern Afghan town of Mazar-e-Sharief was seized by Taliban militias in heavy fighting three weeks ago. Eleven Iranians, including a journalist for the state-run Islamic Republic News Agency, had been missing from Teheran’s consulate in Mazar-e-Sharief since the city – for years a base of anti- Taliban forces – fell to the radical Islamists.

“This act of war crime must be condemned, those responsible arrested and extradited to Iran for prosecution,” wrote U.N. Ambassador Hadi Nejad-Hosseinian in a letter to Dahlgren.

Abdul Hakim Mujahid, designated by the Taliban as Afghanistan’s ambassador to Pakistan – which is one of only three countries to recognise Taliban rule – said from Islamabad that the Taliban also was investigating the killings and would issue a full report next week. One source at the United Nations told IPS that the Taliban blamed the killings on “radical elements” acting on their own after the fall of Mazar-e-Sharief.

Some US-based pro-Taliban groups, including the Afghan Cultural Association of New York, the Council of Cooperation of Afghan Immigrants in Northern California and the Afghan Doctors Association-USA, blamed Iran for the hostilities.

In a statement Friday, the groups argued, “The presence of Iranian ‘diplomats’ and other military personnel was a direct violation of the U.N. Charter,” and added that the troop build-up is “threatening the sovereignty and territorial integrity of Afghanistan”.

Nejad-Hosseinian decribed the deaths as “cold-blooded murder” and contended that it is only the latest atrocity committed by the Taliban. “The continued policy of militarism by the Taliban, fueled from outside, (the) indiscriminate bombing of civilian and defenseless people in Bamiyan, and (the) ruthless implementation of a policy of ethnic cleansing by the Taliban which are tantamount to other acts of war crimes have seriously escalated tension and jeopardised peace and security in the region,” he wrote.

Human rights groups, including Amnesty International, have accused the Taliban of committing massacres and other atrocities in the central province of Bamiyan – home to the ethnic Hazara minority, who are mostly members of the Shi’a sect of Islam, as are most Iranians – over the past month. The Taliban comprises comprised mostly radical Hanafi Muslims from the religion’s Sunni orthodoxy and, in the past, has been accused of anti-Shi’a bias and persecution of Hazaras.

Laili Helms, a Taliban spokeswoman in New York, told IPS recently that despite the allegations against them, the Taliban militias were drawing support among Bamiyan’s Hazara community. “The Hazaras are increasingly giving them a chance” to establish rule over all Afghanistan, Helms said, adding that most Afghans were tired of the country’s 20-year war.

This week, however, heavy fighting raged through Bamiyan as the Taliban moved to control the province. Some UN diplomats believe that the Bamiyan fighting is a key cause of Iran’s growing concern and its pledges in recent days to defend its citizens against the Taliban.

The crisis also was a problem for Pakistan, which supported the Taliban but clearly was now anxious about the rising tensions with its neighbour, Iran. Pakistan assured Iran that Iranians in Mazar-e-Sharief would be safe, and had lobbied the Taliban in recent days to work with Teheran in returning any Iranians still in Afghanistan.

One UN officials said that Secretary-General Kofi Annan was working behind the scenes to resolve the growing problems between Kabul and Teheran. However, the United Nations’ own influence on the Taliban, dominated by young students trained in religious schools based in northern Pakistan, has been limited.

UN officials and relief workers have been largely absent from Afghanistan following an Aug 20 US missile attack on the country, designed to punish supporters of Osama bin Laden, an Afghan-based Saudi financier linked to bombings of US embassies in Kenya and Tanzania.

UN mediators also have been repeatedly frustrated in efforts to bring about a cease-fire between the Taliban and its opponents, including the Iran-backed Shi’a group Hezb-e-Wahdat.