A decades-old border dispute over fertile farmland between Sudan and Ethiopia is feeding regional rivalry -- and even sparking fears of the broader conflict, analysts say.

The border quarrel is over Ethiopian farmers cultivating land claimed by Sudan, but it is stoking wider tensions over Ethiopia's Blue Nile mega-dam, which downriver Khartoum and Cairo view as a threat to their water supply.

The territorial argument also comes amid the fallout from unrest in Ethiopia's troubled Tigray region, with tens of thousands of refugees have fled into Sudan.

Who owns the land?

Arguments over Al-Fashaqa, an agricultural area sandwiched between two rivers, where Ethiopia's northern Amhara and Tigray regions meet Sudan's eastern Gedaref state, date back decades.

With the zone contested, the exact area is not clear, but Al-Fashaqa covers some 12,000 square kilometres (4,630 square miles), an area claimed by both Sudan and Ethiopia.