The United States has said it’s “gravely concerned” over the escalation of tensions and reports of ongoing fighting in the western parts of Ethiopia’s conflict-torn Tigray region.

The concerns follow comments from the European Union foreign policy chief, Josep Borrell, who has urged member states to consider imposing sanctions over the crisis.

The US reiterated its call for a negotiated ceasefire, as clashes were reported between forces from Tigray and Amhara regions along disputed areas.

Fighters loyal to the region’s main political group, the Tigray People’s Liberation Front (TPLF), now claim to have taken the towns of Korem and Alamta as they advance towards the south.

It is feared continued fighting could significantly undermine efforts to provide much needed humanitarian assistance to millions of civilians caught in the crossfire.

Thousands are believed to have been killed in the eight-month long war, while more than two million people have been forced from their homes.

Last month, fighters loyal to the TPLF recaptured key cities - including the regional capital - in Tigray. The government announced a unilateral ceasefire and withdrew its troops.