Sudan's President Omar al-Bashir has ordered the opening of his country's border with South Sudan for the first time since the south seceded in 2011 to become an independent nation.
Relations have been tense between the two countries since the south declared independence following a long civil war, taking with it three-quarters of the country's oil.
Sudan's SUNA state news agency said late on Wednesday that al-Bashir issued a decree ordering the opening of the border and directed "the relevant authorities to take all measures required to implement this decision on the ground".
The move comes after South Sudanese President Salva Kiir on Monday ordered his country's military to retreat 5km from the border.
He then went on to announce a normalisation of relations between the two neighbours on Tuesday, in response to al-Bashir agreeing to cut transit fees for South Sudanese oil crossing its territory via a pipeline to the Red Sea last week.
The decision to close the border in 2011 came shortly after the start of an uprising in Sudan's South Kordofan state by the Sudan People's Liberation Movement North.
The two states, which accuse each other of backing armed rebellions against their respective governments, decided in November to revive the demilitarised zone which is on the border and had been agreed upon in 2012.
READ MORE: South Sudan marks two years of war
South Sudan descended into conflict in December 2013 after Kiir accused his former deputy Riek Machar, whom he had sacked earlier that year, of plotting a coup.
Clashes that followed set off a cycle of retaliatory killings that have split the world's newest country along ethnic lines, forcing one million people from their homes, and leaving four million hungry.