Sudan sent military reinforcements to its border with Ethiopia after it said an army unit was ambushed in the area by militiamen linked to the Ethiopian army, killing an officer and soldiers.
Sudan and Ethiopia have had a long history of border disputes that occasionally flare into armed clashes.
The latest incident, on Saturday, followed a similar one in May in which a senior Sudanese officer was killed in fighting that forced thousands of Sudanese residents in the border area to flee their homes.
The military did not give details on the size of the reinforcements sent to the border, but it is likely to fuel tension at a time when at least 50,000 residents of Ethiopia’s restive Tigray region have fled fighting between the government and insurgents, and found refuge in Sudan.
The influx of the refugees and the continuing fighting have prompted Sudan’s military to increase its troop numbers on the border with Tigray to stop the rebels using Sudanese territory.
The clash followed a dramatic improvement of relations between Ethiopia and Sudan since the 2018 rise to power of Prime Minister Abiy Ahmed in Addis Ababa and the removal a year later of Sudanese dictator Omar Al Bashir.
Border tension adds a new layer to Sudan’s array of problems, which range from a collapsing economy and civil strife to uneasy relations between the military and civilian members of the transitional government that succeeded Al Bashir.
Sudan’s Prime Minister, Abdalla Hamdok, recently visited Addis Ababa and agreed with Mr Abiy to revive a joint committee to negotiate the demarcation of the border.
Mr Hamdok’s government on Wednesday condemned Ethiopian “aggression” and stated its full support for the armed forces' efforts to protect the country’s territory.
Sudan has long claimed that Ethiopia was illegally controlling areas straddling their border.
One of those, Al Fashqah, was wrested from Ethiopian control this month, ending 25 years of occupation.
The neighbours are also at odds over a huge Nile dam being built by Ethiopia.
Sudan maintains that operating the hydroelectric dam without sharing data poses a danger to its own power-generating dams on the Nile and leaves the country at risk of the deadly floods that often hit it in late summer.
It also sets Sudan an extra challenge as its transition to democratic rule repeatedly runs into obstacles with the military and civilian wings of the government.
They publicly bicker over issues including control of the army’s business interests, security in major cities and charges that the generals meddle in foreign policy behind the government’s back.
The latest power struggle centred around a newly formed, 29-member council with the task of planning the transition to democratic rule and resolving disputes between government factions.
Civilian members said the mandate given to the council by Gen Abdel Fattah Al Burhan, Sudan’s de facto head of state, encroached on the authority of the Cabinet and a proposed, 300-seat Parliament.
But the council, on which Mr Hamdok and his backers in the pro-democracy movement sit, met for the first time on Wednesday.
A statement issued after the meeting suggested that the dispute has been resolved.
It said participants agreed that the council’s authority would not encroach on that of the executive branch of government and would instead focus on supporting all parties to guide the country through the transitional period, which ends in 2022.
The council also groups Gen Al Burhan, five other generals and representatives of rebel movements with which the government signed a peace deal in October.