Ethiopia warned Friday it could deploy its "entire defensive capability" after rebels from war-hit Tigray rebuffed calls to pull back from neighbouring regions.

The ramped-up rhetoric from Prime Minister Abiy Ahmed's government played into fears that Ethiopia's widening war could soon become more violent, even as the UN and the US appeal for a ceasefire so glaring humanitarian needs can be met.

The government "is being pushed to mobilise and deploy the entire defensive capability of the state if its humanitarian overtures for a peaceful resolution of the conflict remain unreciprocated," the foreign ministry said in a statement.

It was not immediately clear what the government had in mind, though troops from various regions have moved towards Tigray in recent weeks to back up the military.

A state media report quoted the Amhara region's security office as saying an offensive would be launched Saturday "to destroy the enemy and reverse the existential threat" posed by rebels.

Northern Ethiopia has been wracked by fighting since November, when Abiy sent troops to topple the Tigray People's Liberation Front (TPLF), the then-ruling party of Tigray which dominated national politics for nearly three decades until 2018.

The church of St. George is one of the rock-hewn treasures of Lalibela, a UNESCO World Heritage Site
The church of St. George is one of the rock-hewn treasures of Lalibela, a UNESCO World Heritage Site AFP / EDUARDO SOTERAS

The move came in response to TPLF attacks on army camps, said Abiy, the 2019 Nobel Peace Prize winner.

Although he promised a swift victory, the war took a stunning turn in June when pro-TPLF forces recaptured Tigray's capital Mekele and the Ethiopian army largely withdrew.

Since then the TPLF has pushed east into the neighbouring Afar region and south into Amhara.

On Thursday, TPLF combatants entered UNESCO heritage site Lalibela in Amhara without a fight, as security forces withdrew ahead of their advance, residents told AFP.

Lalibela is home to 12th-century rock-hewn churches that are a major tourist draw in peacetime, as well as an airport.

Rebel spokesman Getachew Reda told AFP the TPLF would continue to secure roads in northern Amhara in a bid to prevent government forces from regrouping.

Ethiopia
Ethiopia AFP / Simon MALFATTO

US officials including aid chief Samantha Power, who visited Ethiopia this week, have urged the TPLF to withdraw and called on all sides to cease hostilities and focus instead on addressing the humanitarian "catastrophe" in Tigray.

But Getachew said "nothing of the sort is going to happen unless the blockade is lifted", a reference to restrictions on aid access.

"We are under siege. We are under blockage. Anything that Abiy is going to use to maintain its chokehold on our people, we'll make sure it doesn't pose a serious problem."

On Friday pro-TPLF forces were in "hot pursuit" of Amhara regional forces who had headed north from Lalibela to the town of Sekota, Getachew said.

US urges Tigray rebels to 'protect' Lalibela site
US urges Tigray rebels to 'protect' Lalibela site US DEPARTMENT OF STATE

He said the TPLF does not intend to hold territory in Amhara and Afar and is instead focused on facilitating aid access.

It remains committed, though, to retaking areas of western and southern Tigray occupied by Amhara forces since the war's early stages, he said.

Amhara leaders have rejected calls by the US and other world powers to exit those territories, claiming they historically fall under Amhara control.

The dispute bodes ill for growing ceasefire calls.

The UN says fighting in Tigray has pushed 400,000 people into famine-like conditions.

UN humanitarian chief Martin Griffiths told a press conference Friday the desperate need for food aid in Tigray would persist into 2022.

The TPLF accuses Abiy's government of blocking aid, and top humanitarian officials continue to decry bureaucratic and other hurdles hindering access.

The government says a unilateral ceasefire it declared in late June was intended to allow aid in, and that the TPLF's subsequent offensive undermines that effort.

On Friday Abiy's office reported an additional 63 trucks of food aid had reached Mekele, taking the total to 220 in recent weeks.

But the foreign ministry said TPLF actions were "testing the government's patience and pushing it to change its defensive mood".

Abiy's spokeswoman Billene Seyoum said Thursday more than 300,000 people had been displaced by recent fighting in Amhara and Afar.

Amhara deputy president Fanta Mandefro told AFP Thursday the rebels were responsible for abuses including killings and sexual assault.

But Getachew dismissed the claims.

The US has urged the rebels to protect Lalibela, but Getachew said the concerns were misplaced.

"We know what it means to protect heritage sites," he said. "Lalibela is our heritage site as well."

Multiple heritage sites in Tigray have been damaged during the conflict, though Tigrayans have generally blamed pro-government forces for the destruction.