Egypt and Sudan had high-level exchanges over the past week, suggesting the neighbours are seeking to resolve a public rift over the dam Ethiopia is building on the Nile.
Sudan was perceived to be favouring Ethiopia after failing to sign a US-brokered agreement on sharing the river's water and the operation of the giant dam.
Egypt signed the accord last month but Ethiopia also refused, saying it wanted to reach a deal with the two downstream nations without foreign interference and that it wanted more internal consultation on the issue.
Sudan, which hopes to receive cheap power from the dam, last week insisted that its name be removed from an Arab League resolution admonishing Addis Ababa for not signing the accord in Washington last month.
It said the resolution would create confrontation between the League and Ethiopia, and that it was not consulted before the resolution was drafted.
A call between Sudan’s transitional head of state Gen Abdel Fatah Al Burhan and Egyptian President Abdel Fattah El Sisi last week was followed by a visit to Khartoum by Mr El Sisi’s close confidant and intelligence chief, Abbas Kamel.
At the weekend, Gen Al Burhan’s second in command, Gen Mohamed Dagalo, visited Egypt and met Mr El Sisi.
The intensity of contacts over a short period suggests that an earnest effort was being made to reconcile or at least narrow the gap between the neighbours.
Meanwhile, Sameh Shoukry, the Egyptian Foreign Minister has been on a diplomatic offensive over the dam this month.
Mr Shoukry went on a nine-nation tour, mostly to Arab nations but also to Paris and Brussels, to brief leaders on where Egypt stood and to complain of Ethiopia's “intransigence”.
“Egypt has always been at the forefront in defending Arab national security," he said this week.
"We expect our Arab brothers to rise in the defence of Egypt’s position."
Hany Raslan, a Sudan expert at Al Ahram Centre for Political and Strategic Studies, said: “Pressure must be exerted on the Sudanese transitional government to amend its position."
Egypt and Sudan are bound by historical ties dating to pharaonic times.
But Egypt’s colonial expansion in Sudan during the 19th century and its hand in Britain's suppression of a pro-independence movement against Turkish-Egyptian rule in the late 1880s, and later occupation of the country, have hung over Cairo’s ties with Khartoum.
Relations have been on a rollercoaster since Sudan gained independence in 1956, with the neighbours often at odds over a wide range of issues.
They include a border dispute, Cairo’s support for many of Sudan’s authoritarian rulers, and what many Sudanese see as its patronising policies and sense of superiority.
Sudan has been drawing closer to Ethiopia in recent years as Addis Ababa’s influence in East Africa has grown.
Its border dispute with Egypt, meanwhile, leads to frequent tension as Cairo refuses to put the issue to international arbitration.
The dam dispute has been compounded by the absence of any prospect for future talks.
An offer by Uganda to host a summit of Nile Basin nations to resolve the matter has yet to make progress.