Reports from Herat suggest Iran is extremely active in the area.

It is said to be helping to rebuild a highway stretching from the Iranian border to Shi'a areas of Afghanistan.

And local people say large numbers of Iranian traders have appeared in Herat city, some offering generous bank credits to Afghans prepared to do business.

Tehran is not alone in such actions.

Many governments are vying to forge political and economic links with the new Afghanistan, hoping to increase their influence in the region.

Tehran is particularly concerned about Washington's spreading influence, fearing a long-term presence of American forces on Afghan soil.

Many people around Herat need help

Western diplomats concede that, despite this, the Iranian Foreign Ministry, which is under the control of Iran's moderate president, has played a broadly positive role in the months following 11 September.

It has denounced terrorism and actively supported Western efforts to establish an interim government in Afghanistan.

But some of Iran's hardline Islamic groups have attempted to undermine that position, accusing the new Afghan administration of being pro-American.

Such groups may fear that rising Western influence in Afghanistan could lead to a more secular and independent form of government there.

Smugglers

Tehran has strongly denied American allegations that it has given refuge to al-Qaeda fugitives.

But it is not inconceivable that hardline groups may have harboured such people without the central government's knowledge.

Despite the Foreign Ministry's insistence that the border is firmly closed, smugglers have managed to spirit tens of thousands of Afghan refugees into Iran in recent years.

There have traditionally been close cultural and economic ties between the Herat region and Iran.

Although the majority of the local Afghan population are Sunni rather than Shi'a Muslims, their language and customs owe more to Persian culture than to the more conservative south of Afghanistan.

During Afghanistan's civil war, Tehran backed anti-Taleban forces and when the current governor of Herat, Ismail Khan, escaped from a Taleban jail in Afghanistan two years ago, he took refuge in Iran.