Chadian rebels have attacked the eastern town of Guereda, neighboring Sudan's war-torn Darfur region.

Fighting is reported to have lasted three hours with government forces clashing with the rebels.

UN offices in Guereda were attacked, and staff have been held at gunpoint.

Meanwhile, Amnesty International (AI) says it has evidence that attacks by Janjaweed militia from Sudan are taking place 150km (93 miles) inside Chad.

The human rights organization says it has proof that these fighters, who are armed and supported by the Sudanese government, have been carrying out killings and mutilations of Chadian villagers, deep inside the country.

"We have seen a dramatic upsurge in ever more brutal attacks on civilians which have occurred further and further into Chad," AFP news agency quotes said Alex Neve, a member of the Amnesty delegation, as saying.

"Yet the Chadian military and police are not even making a token effort to protect their own citizens," he said.

On Friday, the United Nations refugee agency airlifted more than 100 tones of relief supplies to Chad to replace stocks which local people looted from a warehouse last weekend when rebels took the eastern town of Abeche.

The goods were taken by local people, but some have been returned following house-to-house searches by the military.

The fresh supplies were flown into the capital, N'Djamena, from Ghana.

The UN says about 90,000 Chadians have been displaced by the recent fighting.

Photo caption

Chadian soldiers patrol the south-eastern town of Am Timan on 27 October 2006 after it was briefly occupied by rebels