UNITA rebels have accused the Angolan government of carrying out air raids in the central Bie province.

A UNITA official, Paulo Lukamba Gato told Portuguese radio that government troop movements were also creating tension in the central highlands.

The United Nations earlier said that renewed fighting in several parts of the country was so serious that a third of a million refugees were now on the move.

The fighting is taking place as the governing party in Luanda, the MPLA, opens its congress meeting.

The future of the peace process is expected to be high on the agenda of the meeting, which will also discuss the MPLA's economic and political policies for the next four years.