Sudan's President Omar al-Bashir visited South Sudan Friday in a sign of easing tensions after the two states ended a row over crucial oil exports and put behind them bloody border battles last year.
It was the first time Bashir travelled to South Sudan since attending the country's declaration of independence on July 9, 2011.
"The only way to solve problems between our two countries is with dialogue," Bashir told a news conference after talks with South Sudanese President Salva Kiir, his former foe in the 1983-2005 Sudanese civil war.
Bashir said the aim of his visit was to "push for implementation" of a September accord that addresses a number of bilateral issues left unresolved when South Sudan broke away in 2011 -- the oil issue chief among them.
South Sudan early last year stopped all of its crude production because of a dispute with Sudan over how much it should pay for shipping its oil through Sudanese pipelines for sea export.
When South Sudan split away, it took with it fields accounting for 75 percent of the oil reserves -- totalling some 470,000 barrels per day -- Sudan used to call its own.
Juba complained that Khartoum was demanding too much for the use of Sudanese pipes and port facilities, and the shutdown cost both countries billions of dollars.
Battles along the two nations' undemarcated border last year involving warplanes and troops then aggravated the situation and raised fears of a return to the level of violence seen in the 22-year civil war.
International pressure eventually reined the two sides into an uneasy standoff.
The September accord sought to solve the disputes. But deals enshrined in the document were not enacted for months, with Sudan notably demanding guarantees from South Sudan that it would halt backing for rebels fighting in Sudan's South Kordofan and Blue Nile states.
Several months of bilateral talks led to a meeting in Addis Ababa last month at which both sides struck agreement on resuming oil flows and on several other pacts, including one for a demilitarised border buffer zone.
South Sudan held a ceremony a week to restart crude production.
But, even as Bashir conducted his visit, accompanied by defence, interior, oil and intelligence ministers, challenges to relations over security reared its head again.
According to Sudanese state television, three people were killed on Friday in Sudan's South Kordofan region by suspected rebels who fired shells on their town.
The attack in the east end of Kadugli town came after similar barrages in October by the rebel Sudan People's Liberation Movement-North (SPLM-N) that killed 18 and forced townsfolk to flee.
The insurgency in South Kordofan and Blue Nile has forced more than 200,000 people to become refugees in South Sudan and Ethiopia.
Analysts and diplomats say there is no doubt South Sudan continued to back the SPLM-N, which was part of its fighting force before independence.