The US envoy to the Horn of Africa is visiting the Ethiopian capital, Addis Ababa, to press for a peaceful solution to the war in the north of the country.

Jeffrey Feltman's visit comes as Tigrayan fighters have made some advances towards the capital in recent fighting.

A police spokesman said many supporters of what he described as "illegal terrorists" had been arrested in Addis Ababa.

The US has authorised the voluntary departure of non-essential government employees.

Britain has urged its citizens to leave while commercial options are still available.

Kenya has increased security along its border with Ethiopia.

Earlier, the head of the African Union, which has its headquarters in Addis Ababa, posted pictures of his meeting with Mr Feltman.