Sudan and South Sudan will normalise ties and start cross-border cooperation, Sudanese President Omar al-Bashir has said.
Bashir made the comments on Friday during his first visit to South Sudan since July 2011 when the south seceded and became an independent state.
"This visit shows the start of cooperation based on a normalisation of relations between the two countries," Bashir said in a speech in the capital, Juba.
South Sudan's Salva Kiir said he had agreed with Bashir to continue a dialogue to solve all outstanding conflicts between the African neighbours.
"Some issues need more discussions," Kiir said, adding that he had accepted an invitation from Bashir to visit Sudan soon, his second trip since the secession.
Bashir was received at Juba airport by Kiir, his former civil war foe and an ex-rebel commander.
A military band played the national anthems of the two countries as the two heads of state greeted South Sudanese ministers assembled to welcome Bashir.
The two nations agreed in March to resume cross-border oil flows and take steps to defuse tension that has plagued them since South Sudan seceded from Sudan in July 2011 following a treaty which ended decades of civil war.
They still have not agreed who owns Abyei province and other regions along their disputed 2,000km border.
Kiir said the two leaders would continue discussions on region.
Bashir had planned to visit Juba a year ago but cancelled the trip when fighting erupted along the border and almost flared into full-scale war.
Speaking alongside Kiir, Bashir said he had ordered Sudan's borders with South Sudan to be opened for traffic.
"I have instructed Sudan's authorities and civil society to open up to their brothers in the Republic of South Sudan," he said.
Meanwhile, two people were killed and eight wounded as suspected rebels shelled the capital of Sudan's war-torn South Kordofan state on Friday.
Residents said the attack struck the east of Kadugli town at about 1:30 pm (10:30 GMT).
They suspected the shells came from the Sudan People's Liberation Movement-North (SPLM-N), but the rebels' spokesman said he did not yet have any information.
South Sudan's secession left unresolved a long list of disputes over territory and how much the landlocked south should pay to export its oil through Sudan.
The new African country shut down its entire oil output of 350,000 barrels a day in January last year at the height of the dispute over pipeline fees - a closure that had a devastating effect on both struggling economies.
The two sides subsequently agreed to restart oil shipments, grant each others' citizens residency, increase border trade and encourage close cooperation between their central banks.
Last week, South Sudan re-launched oil production with the first oil cargo expected to reach Sudan's Red Sea export terminal at Port Sudan by the end of May.
Both nations also withdrew their troops from border areas as agreed in a deal brokered by the African Union in September.
About two million people died in the war that was fuelled by divisions over religion, oil, ethnicity and ideology and ended in 2005 with a deal that paved the way for Juba's secession.