Ethiopia's government reaffirmed its commitment to peace talks in Tigray on Monday, but did not respond to African Union calls for a ceasefire, instead vowing to take "defensive measures" such as seizing airports and other federal facilities in the region.

"These measures are necessitated not only by the TPLF's (Tigray People's Liberation Front) repeated attacks, but also by its active collusion with these hostile foreign powers," the Government Communication Service said in a statement.

As fighting intensifies in war-torn Tigray, AU Commission chair Moussa Faki Mahamat called for a "immediate, unconditional ceasefire" and urged both sides in the nearly two-year conflict to "recommit to dialogue" on Sunday.

Tigrayan authorities said on Sunday that they were "ready to abide by an immediate cessation of hostilities" and urged the international community to put pressure on the government to come to the table.

On Monday, Addis Abeba stated that it is "committed to the peaceful resolution of the conflict through the AU-led peace talks."

However, it stated that this would be followed by "defensive measures" to protect Ethiopia's sovereignty and territorial integrity from internal and external threats.

"As a result, it is critical that the Government of Ethiopia take immediate control of all airports, other federal facilities, and installations in the region," the statement said.

UN Secretary-General Antonio Guterres, the United States, and other Western powers have expressed concern about the escalating violence in Tigray and called for a peaceful resolution to "this catastrophic conflict."

Shire, a 100,000-person city in northwest Tigray, is of particular concern, as Ethiopian and Eritrean troops have launched a joint offensive, with civilian casualties reported.

An International Rescue Committee aid worker was among three civilians killed in an attack in Shire on Friday, where witnesses reported heavy shelling in recent days.

According to the government, its army strives to "avoid combat operations within urban areas in order to avoid civilian casualties."

"The Ethiopian Government deeply regrets any harm that may have been inflicted on civilians, including humanitarian personnel," the GCS said, adding that such incidents would be investigated.