A 31-year-old man died after it is believed he was struck by a car in County Tyrone.
The incident happened just outside Dungannon on the Moy Road shortly before 0400 GMT on Sunday.
The road is closed between the old Moy Road and Grange Road and drivers have been asked to avoid the area.
Car drove on
Following a separate incident outside Armagh, the police are appealing for witnesses to a crash in which a 21-year-old man was seriously injured.
He was struck by a car while walking along the driveway of a nightclub off the Drumcairn Road at about 0100 GMT on Sunday.
The car did not stop and was driven away towards Armagh.
The 21-year-old is said to be critically ill in hospital.
Pensioner killed
On Friday night a 70-year-old woman was killed when she was struck by a car while crossing the road at Kiln Hill in Armagh.
Emily Rebecca McKenna had lived at Ballinahone Close.
Meanwhile, a 17-year-old man injured in a road accident near Ballymena in County Antrim on Tuesday has died in hospital.
Robert Wilmont, from Ballymoney was a back seat passenger in a BMW which crashed into a field at Glaryford.