Somali Islamists and pro-government troops fought heavy artillery and mortar duels yesterday, witnesses and officials said, in a sixth day of clashes round the encircled government base of Baidoa.

The Islamists urged foreign Muslim fighters on Saturday to join their ?holy war? against Ethiopia. They accuse Christian-led Ethiopia, a key US ally in its war against terrorism, of invading Somalia.

?Fighting is going on from one part of the country to the other. The Islamic Courts have ignited the war they promised yesterday,? Information Minister Ali Ahmed Jama, in Baidoa, told Reuters. ?They will lose in this fighting.?

The witnesses and officials said the fighting was raging on four fronts.

Both sides say they have killed hundreds since fighting began on Tuesday. Aid agencies say dozens have died.

The most sustained fighting to date between the two sides has heightened fears of a major regional war that would ensnare Horn of Africa rivals Ethiopia and Eritrea and trigger possible suicide bombings in East Africa.