Police today escaped injury after being pelted by petrol bombs and other missiles in Craigavon, Co Armagh.
The violence followed a security operation in the Tullygally and Drumbeg area of the town after bomb warnings were received yesterday.
Numerous police vehicles were damaged with bottles, stones and at least one blast bomb hurled at officers.
Motorists have been advised to avoid the area.
Police were also attacked with petrol bombs and other missiles in Belfast early this morning.
The trouble in the south and east of the city was centred in the nationalist Markets and Short Strand areas on each side of the River Lagan.
The Police Service of Northern Ireland (PSNI) said they were attacked when they responded to reports of youths involved in sporadic stoning of cars in the two areas — spreading from the lower Ormeau Road in the south of the city to the lower Newtownards Road in the east.
A small number of petrol bombs were thrown in the Cromac Street and Pitt Park areas of the Markets when police arrived and stones were thrown at them elsewhere.
A number of roads were closed and traffic diverted away from the areas for a time.
A Police Service spokesman said police liaised with community representatives to restore calm to the affected areas.
There were no reports of any injuries or arrests.
Sinn Féin Assembly member Alex Maskey condemned those responsible for what he called "wanton disregard of the good name of their area, never mind the safety of people passing."
Mr Maskey added: "It is very disappointing that we had a number of young people gathered last night who started to thrown stones and other missiles at passing vehicles — some of which contained families and young children.
"It is just unacceptable and very, very regrettable that what was a small number of young people have caused this damage."
He said it flew in the face of the efforts of people in the nationalist areas to work with young people and provide activities for them.
PA