2005 - Sudan's government signs a peace deal with southern Sudan People's Liberation Movement (SPLM) rebels, ending decades of civil war.
-- Abyei, a fertile, oil-producing area on Sudan's ill-defined north-south border, claimed by both sides, was a key battleground during that conflict.
-- The peace deal does not settle the ownership of the area or set its borders but promises Abyei residents a referendum over whether they want to join the north or south. It also promises southerners a separate referendum on whether to secede from the north.
May 2008 - Clashes in the Abyei region -- close to oil fields claimed by both the north and the south -- kill at least 90, drive 50,000 from their homes and burn down Abyei town.
June 21 - The former north-south foes agree that an international court should decide on Abyei's boundaries.
July 22, 2009 - The Permanent Court of Arbitration in The Hague adjusts boundaries drawn up by an earlier panel, pulling in Abyei's borders to the north, east and west. Northern and southern leaders promise to respect the ruling.
-- Maps of the new boundary published in The Hague leave the area's key Heglig and Bamboo oilfields outside Abyei, placing them in the north Sudan district of Southern Kordofan while leaving huge tracts of fertile land inside Abyei.
-- Arab Misseriya nomads, linked to the north, protest against the border change saying it robs them of pasture land. Members of the south-linked Dinka Ngok tribe, that live in Abyei, welcome the ruling.
July 27 - North and south Sudanese leaders trade accusations over control of oilfields and details of the Abyei referendum just five days after agreeing the ruling.
Dec. 29 - Sudan passes a law authorising the referendum on southern independence. The next day the Abyei referendum law is also passed.
Oct. 12, 2010 - The latest round of north-south talks on Abyei fail. Two days later north Sudanese leaders say it is impossible to hold the referendum on time.
Jan. 9, 2011 - Millions of jubilant south Sudanese vote to split from the north in their secession referendum. The separation is due to take place on July 9, 2011. The Abyei referendum does not take place.
March 30 - Sudan's north and south have deployed forces with heavy weapons to Abyei, the United Nations says.
April 27 - Bashir says he will not recognise South Sudan as an independent state if it claims the oil-producing Abyei region. The south's draft constitution, seen by Reuters, includes a claim to Abyei.
May 20 - South Sudan's army accuses the north of using tanks and artillery in attacks on four villages. North Sudan's army accuses the south of ambushing northern troops.
May 21/22 - Khartoum sends tanks into Abyei town, the area's main settlement, forcing thousands to flee. The north says it is clearing out southern troops that have moved into the area, breaking earlier agreements.
May 26 - The south's president Salva Kiir says there will be no war over the northern occupation and it will not derail independence.
May 28 - The northern army stops military operations.
May 31 - Representatives from north and south Sudan agree to set up a Common Border Zone between North and South Sudan, which is to be demilitarised and monitored and patrolled, the AU says.
June 6 - The U.N says that around 96,000 people have fled the region following the fighting.
June 12 - Bashir agrees to pull northern troops out Abyei before the south secedes on July 9, diplomats say.
June 13 - North and south Sudan agree in principle to demilitarise Abyei and to deploy Ethiopian peacekeeping troops in the region, an African Union official says.
June 20 - North and south Sudan sign an agreement to demilitarise the Abyei region, former South African President Thabo Mbeki says. The agreement provides for the Sudanese armed forces withdrawal and for the deployment of Ethiopian forces.