Masood's reputation was based on his military brilliance

If he is dead - or incapacitated - it will have serious implications both for Afghanistan and for its neighbours.

What all of them fear is the spread of the Taleban's brand of Islamic militancy throughout the region. They also see Afghanistan as a source of drugs, terrorism and instability.

It is because of this that they have been backing the assorted groups which make up the anti-Taleban Northern alliance.

Mr Masood kept that alliance together - and there is a widespread fear that without him the alliance would fall apart.

International support

Ahmed Shah Masood's reputation was built, first and foremost, on his brilliance as a military commander during the war against the Soviet occupation.

Tajikistan fears the spread of radical Islam

Besides his formidable reputation as a soldier, his charisma has managed to appeal to the disparate groups that make up the opposition - cutting across ethnic lines.

But Mr Masood, an ethnic Tajik, has also received financial and military assistance from a range of international supporters, including his old enemy Russia.

Tajikistan and Uzbekistan are concerned with the growth of radical Islam within their borders and hold the Taleban responsible.

And Russia accuses the Taleban of supporting and training Chechen rebels.

Shiite Iran, on the other hand, has been a strong backer of the Shia minority in Afghanistan, largely confined to the Hazara ethnic group in the central province of Bamiyan.

For its part, the Taleban receives strong support from Pakistan which, along with Saudi Arabia and the United Arab Emirates, recognises it as the legitimate representative of Afghans.

US interests

Officially, the countries opposed to the Taleban have been calling for a broad-based government in Afghanistan that would represent all the various ethnic groups.

US policy is dictated by the Osama bin Laden factor

This is a position backed by India and the United States.

The American policy towards Afghanistan is dictated by the Taleban's protection to Washington's biggest enemy, the Saudi dissident Osama bin Laden.

But the US - and several countries in the region - are also keen to commercially exploit the vast oil and gas reserves in Central Asia, and believe that Afghanistan holds the key.

Several countries are exploring the idea of building a pipeline from Central Asia across Afghanistan to Pakistan and beyond - something that would be impossible without a stable Afghanistan.

Ahmed Shah Masood was also virtually alone among Afghan leaders, he was known and respected in the West.

Earlier this year he got a warm reception in France and at the European parliament, where he was seen as the symbol of the Afghan struggle against a backward and repressive regime.