UN Secretary General Antonio Guterres on Monday called for an immediate end to hostilities and the withdrawal of Eritrean forces from Ethiopia.
Mr Guterres, who joined the US, western powers and the African Union in voicing alarm over the worsening violence in the Tigray region, told reporters the situation in Ethiopia is “spiralling out of control”.
“Violence and destruction have reached alarming levels. The social fabric is being ripped apart,” he said. “There is no military solution.”
In a statement on Monday, the Ethiopian government accused the Tigray People's Liberation Front (TPLF) of launching a third round of attacks soon after Addis Ababa announced its readiness for African Union-led peace talks “without preconditions”.
The statement said the government was forced to take “defensive measures” to safeguard the sovereignty and territorial integrity of the country and thus would assume “immediate control of all airports”.
The government statement also warned civilians and humanitarian workers to “distance themselves from TPLF’s military assets”.
Ethiopia is under pressure to begin peace talks that were initially set to begin this month in South Africa. No new start date has been announced.
Moussa Faki Mahamat, the chairman of the African Union Commission, on Sunday urged an “immediate, unconditional ceasefire” in northern Ethiopia.
Fighting resumed between Tigrayan rebel forces and Ethiopian government troops in August, bringing an end to a ceasefire in place since March that had allowed humanitarian aid to enter the region.
The UN says millions have fled their homes and that hundreds of thousands are close to famine.
Mr Guterres urged all parties to allow and enable the “rapid and unimpeded passage of humanitarian relief for all civilians in need”.
Samantha Power, head of the US Agency for International Development, said the escalating conflict in northern Ethiopia risks additional atrocities and warned that loss of life is intensifying, particularly around Shire.
“Recent indiscriminate attacks by the Ethiopian National Defence Forces and Eritrean Defence Forces in Shire, and reports that Eritrean forces may soon take control of civilian population centres, are gravely concerning,” Ms Power wrote on Twitter on Sunday.