Now it appears one of them may be near to victory - the radical Islamic students of the Taleban who now control around 90% of the country.

But who are the forces ranged against the Taleban and is there really any united opposition to the Taleban militia?

Internal divisions

The so-called Northern Alliance of anti-Taleban groups are a disparate and divided force. Their opposition to the Taleban control is based on ethnic, cultural and religious differences. But political intrigue and personal grudges between the opposition commanders has often meant they have proved more effective when fighting alone than as an alliance.

Most of the warring factions are equipped by powerful overseas backers

Mutual trust is a commodity in short supply among the Taleban's opponents - last May, when the Taleban first threatened Mazar-e-Sharif, the most powerful opposition figure at the time, General Abdul Malik, briefly switched allegiance to the Taleban forcing his ally General Abdul Rashid Dostum to flee.

Shortly after, General Malik turned his guns once more trapping many Taleban fighters who were killed or imprisoned.

Months later he was forced to retreat from Mazar-e-Sharif leaving the city for General Dostum to return.

The question of ethnicity

Opinions vary as to the importance of ethnicty in opposition to the Taleban, but some observers say that the recent conflicts have accentuated racial and religious differences amongst Afghans.

Although mainly ethnic Pashtuns the Taleban insist they are not a nationalist party

Certainly the strict Sunni Islamic orthodoxy enforced by the Taleban makes it unlikely that they will ever see eye-to eye with the Shia Hazaras, led by Abdul Karim Khalili, who live in the mountainous central region of Afghanistan. Their Shia faith has given them strong links with Iran raising Taleban suspicions that they are a force directed from Tehran.

Indeed, almost all the Afghan militias have powerful overseas backers with Russia, the Central Asian republics, Pakistan and Saudi Arabia also known to have given their backing to one group or other.

Even if the Taleban do conquer most or all of northern Afghanistan, they will find it difficult to rule there. The mostly Pashtun Taleban are not popular in many areas of the north, where the inhabitants are ethnic Uzbeks and Tajiks.

Dostum and the Uzbecks

General Dostum: his fondness for whisky is one of many attributes that do not endear him to the Taleban

The Uzbeks are led by General Abdul Rashid Dostum, formerly a general during the Communist era who is believed to receive considerable assistance from Uzbekistan and from Russia via the central Asian republic.

His opposition to the radical brand of Islam practiced by the Taleban is matched by their denunciation of his more relaxed approach to secular activities.

It is General Dostum's forces who initially received the full force of the Taleban's recent advances, including the fall of his headquarters at Mazar-e-Sharif.

Massoud's Tajik forces

Commander Massoud: Veteran miltary leader

The Tajiks are led by Commander Ahmad Shah Massoud - the military chief of the government ousted by the Taleban two years ago. He too is believed to receive considerable outside assistance via an airbase in Tajikistan.

From his time organising the resistance to the Russian military invasion, he is widely regarded as a politically skillful and experienced miliary tactician. But he remains in essence a warlord and does not make an easy or stable ally.

Now, it seems, Commander Massoud's forces are preparing to defend his Panjshir valley stronghold in the north-west of the country.

According to one report, radio broadcasts have been calling on elderly people, women and children to leave valley to avoid a possible blockade. The commander may be anxious that they may not be enough supplies to sustain civilians if fighting goes into the winter.

Bleak outlook

At the moment, the opposition's prospects look bleak. A lot may depend on whether they can, for once, unite against their common enemy and reopen some of their vital supply lines.

As for the Taleban, they will be hoping that their more cautious military strategy during their latest offensive will mean that they can hold on to Mazar-e-Sharif and go on to take the whole country.

But they have celebrated victories in the past, only to see them reversed.

During their previous occupation of Mazar-e Sharif last year, a turning point came when ethnic Hazaras rebelled against house to house searches being carried out by the Taleban. Some reports from the city suggest that such searches may be starting again.