Aid agencies say supplies are desperately needed in the north

And as the UN World Food Programme (WFP) began a major aid operation in the capital Kabul, a spokesman from the agency said fears of an aid crisis this winter were dissipating rapidly.

"With the opening of the Friendship Bridge in Uzbekistan we are able to reach more people than ever before," said Mike Huggins.

"We are trying to reach six million people and we believe we are getting ever closer to that goal."

Thousands of people queued for the supplies at 16 collection points across Kabul.

At some points, there were chaotic scenes as people jostled and pushed forward to get a single sack of wheat.

Click here for map of the border area of northern Afghanistan

In another development, the Tajik Government has reopened a ferry crossing to Afghanistan across the Pyandzh river,

A convoy of more than 20 trucks from Russia was reported to have crossed the river on Sunday morning and to be on its way to Kabul.

Decision welcomed

Uzbekistan has been under strong international pressure to reopen the Friendship Bridge as the harsh winter arrives, amid mounting concern about the welfare of Afghans displaced by fighting.

The train, pulling about 15 coachloads of grain and flour provided by the WFP and the Uzbek Government, shunted across the midway line of the bridge marking the border between the two countries and came to a halt on the Afghan side.

Aid is currently being transferred across the border by barge

A sign in Russian on the side of the coaches read: "Aid from the Uzbek people to the fraternal people of Afghanistan".

The train was met by the ethnic Uzbek Afghan warlord Abdul Rashid Dostum, who inspected the load.

International aid agencies welcomed the announcement that the bridge was to be re-opened.

A spokesman for the United Nations Children's Fund, Rudy Rodrigues, told the BBC he was delighted with the news, which he said would greatly speed up the delivery of aid.

We are sitting here hungry, on the brink of starvation, and nobody is interested in our plight

Refugee near Mazar-e-Sharif

The journey by road to Mazar-e-Sharif, the site of a major Afghan refugee camp, takes just 40 minutes along this route.

But without the bridge, it can take up to 10 days to deliver aid supplies to northern Afghanistan, using routes through Turkmenistan and Pakistan.

The bridge was closed in 1997 after serious clashes erupted between Taleban and opposition forces, sparking fears in Tashkent that violence could spread across the border.

During the current US military campaign against the Taleban regime, the Uzbek authorities have allowed the UN to ship aid by barge across the river, but agencies warned that this was insufficient to get supplies to the people who most needed them.

'Children dying'

There are an estimated 150,000 refugees living in flimsy tents in a refugee camp near Mazar-e-Sharif, where snows have arrived and temperatures drop below freezing every night.

Aid agencies say young children are already dying due to lack of warm clothing, and temperatures are expected to fall further in the days ahead.

Mazar-e-Sharif is regarded by the aid agencies as a key distribution point for supplying northern Afghanistan and for sending aid down to the central highlands, where many Afghans will soon be blocked off by snow.