About 2,500 Ethiopians have escaped across the border to Sudan from fighting in the restive Tigray region, with the exodus likely to swell fast, an official said.

Hundreds have died in airstrikes and fighting amid fears that Ethiopia could slide into civil war given deep animosity between the Tigrayans and Abiy, who comes from the largest Oromo ethnic group.

With access blocked to Tigray and communications largely down, it was hard to verify the state of the conflict.