A decades-old border dispute between Sudan and Ethiopia is pouring fuel on a rivalry that analysts warn could flare into a broader conflict.
Ethiopian Prime Minister Abiy Ahmed insisted Tuesday his country does not want war with Sudan, calling for tensions over the Al-Fashaqa region to be resolved peacefully.
Ethiopian farmers have long worked in the fertile border zone, but the area is also claimed by Sudan.
Tensions have grown since fighting in Ethiopia's Tigray region sent tens of thousands of refugees fleeing into Sudan late last year.
Reports of deadly clashes between Sudanese and Ethiopian forces in Al-Fashaqa also come as Ethiopia faces off with Sudan and Egypt over Addis Ababa's Blue Nile dam, a hydro-electrict megaproject the downriver nations say threatens their vital water supplies.
Abiy, already grappling with Ethiopia's internal conflicts, said Tuesday his country "is not ready to go to battle".
But Sudan has insisted it will only hold talks if Ethiopia admits that Al-Fashaqa is Sudanese territory.
Arguments over Al-Fashaqa, between two rivers where Ethiopia's Amhara and Tigray regions meet Sudan's Gedaref state, date back to colonial times.
Al-Fashaqa covers some 12,000 square kilometres (4,630 square miles), but analysts point to a flashpoint zone directly along the border, covering some 250 square kilometres (just under 100 square miles).
Treaties signed during the colonial era drew the international boundary east of Al-Fashaqa, giving the land to Sudan, said East Africa expert Alex de Waal, a professor at Tufts University.
But over the years, thousands of Ethiopian farmers have grown crops there during the rainy season, despite being periodically expelled by Sudanese forces.
Relations between Khartoum and Addis Ababa nosedived in 1995 after a failed attempt to assassinate Egypt's then-president Hosni Mubarak while he visited Addis Ababa.
Ethiopia blamed Sudan for the attack and sent forces into Al-Fashaqa.
Since then, thousands of Ethiopian farmers have settled in the area, farming and paying taxes to Ethiopia.
Talks between Khartoum and Addis Ababa over the years have never produced a final deal on a border.
Al-Fashaqa abuts Ethiopia's troubled Tigray region, where deadly conflict erupted in November between Ethiopia's federal and Tigray's regional forces.
Khartoum sent troops into the Al-Fashaqa region "to recapture the stolen lands and take up positions on the international lines," Sudanese state media reported.
The fighting in Tigray sent over 60,000 Ethiopian refugees fleeing into Sudan, but the UN says arrivals have declined, with Ethiopians reportedly blocked at the border by "armed actors".
Sudanese military expert Amin Ismail said authorities feared the situation in Tigray could "slip out of control" allowing fighters to infiltrate into Sudan.
Ethiopian premier Abiy has leaned heavily on security forces from his country's Amhara region during the fighting in Tigray.
Many Amhara officials view Al-Fashaqa as rightfully theirs, and some analysts fear Abiy will struggle to rein in their ambitions.
In December, Khartoum dispatched reinforcements to Al-Fashaqa after "Ethiopian forces and militias" allegedly ambushed Sudanese troops, killing at least four soldiers.
That sparked deadly clashes and mutual accusations. Sudan claims it has seized back large parts of the region, while Addis Ababa has accused Khartoum of "invading" Ethiopian territory and warned it could respond militarily.
But Abiy sought to cool tensions on Tuesday, telling parliament: "We don't need war. It is better to settle it in a peaceful manner."
Sudan and Ethiopia both face daunting domestic economic and political challenges.
Sudan is navigating a rocky transitional period following the April 2019 ouster of dictator Omar al-Bashir.
Aside from Tigray, Ethiopia faces internal unrest including in the Benishangul-Gumuz and Oromia regions.
Abiy said Tuesday his country "has many problems, and we are not ready to go to battle."
Sudan's head of state Abdel Fattah al-Burhan has previously ruled out talks unless Ethiopia acknowledges Fashaqa belongs to Sudan.
But Khartoum announced Tuesday it would accept Emirati mediation in talks covering both the border and Ethiopia's vast new dam on the Blue Nile.
The border issue has magnified strains in ties between Ethiopia and Sudan, which along with Egypt objects to Ethiopian plans to fill and operate the Grand Ethiopian Renaissance Dam, Africa's largest hydroelectric project.
Sudan fears the dam will threaten its own waterworks unless there is a binding deal over the GERD's operation.
Egypt, which depends on the Nile for some 97 percent of its water, sees the dam as an existential threat.
Analysts say the Al-Fashaqa issue, while separate from the dam, adds to those tensions.
"There cannot be an all-out military confrontation," said Sudanese military expert Ismail.
"It is simply not in the interest of both countries... It will be a major risk for both sides."
