'Pakistan, Iran and Tajikistan must reopen their borders and provide protection to Afghan refugees. However they should not bear a disproportionate cost - the international community must assist,' the organisation said.

Before the current crisis at least 1.1 million Afghans were internally displaced people due to drought, armed conflict and food shortages. There are already some two million Afghan refugees in Pakistan. Now several hundred thousand are on the move fearing imminent attack. According to some reports more than 100,000 people have left Kandahar alone, the seat of the Taleban.

There are many obstacles for people seeking to flee; many are too poor to obtain transport, many are too weak to move. Even though there is said to be 2-3 weeks supply of food, with the withdrawal of foreign aid workers, food distribution has come to a virtual standstill.

In the last few days Pakistani security forces have reportedly sealed the border with barbed wire in a number of places - despite UNHCR appeals not to turn back refugees. Only those with valid visas are currently allowed to enter but Pakistani authorities have ceased issuing permits altogether. Up to 15,000 Afghan refugees have reportedly made it through in the last week but hundreds of people have been turned back at the Pakistan border. Despite closing its borders, Pakistani authorities have reportedly begun to make arrangements for those who flee Afghanistan but such efforts may be too little too late for the thousands approaching the border.

Neighbouring states have obligations under international law, in particular the principle of non refoulement, which prohibits states from returning anyone against their will directly or indirectly, to another country where they risk serious human rights abuses.

'The people of Afghanistan have suffered conflict and famine for decades. The international community must offer protection and relief immediately and provide adequate resources to the UNHCR for it to carry out its mandate in an effective manner,' Amnesty International said.