Ethiopia's government yesterday denied that northern forces whom its troops have fought for a month would be able to mount a guerrilla insurgency, while diplomats said a United Nations team was shot at while trying to visit a refugee camp.

Federal troops have seized the regional capital Mekelle from the former local ruling party, the Tigray People's Liberation Front (TPLF), and declared an end to their month-long offensive.

But TPLF leaders say they are fighting back on various fronts around Mekelle. Ethiopia experts fear a drawn-out insurgency with a destabilising impact around east Africa.

"The criminal clique pushed a patently false narrative that its fighters and supporters are battle-hardened and well-armed, posing the risk of protracted insurgency in the rugged mountains of Tigray," Prime Minister Abiy Ahmed said in a statement.

"It also claimed that it has managed to undertake strategic retreat with all its capability and regional government apparatus intact."

There was no immediate TPLF response.