Two youths, both aged 15, have been arrested in Lurgan after police were attacked with petrol bombs.
Two officers were injured during the sporadic disturbances in the Kilwilkie estate area on Monday afternoon.
The teenagers were detained on suspicion of a range of offences including riotous behaviour and criminal damage.
The officers’ injuries are not believed to be serious.
Burning bins were also placed on the railway line disrupting rail services between Newry and Lisburn.
A van was hijacked and set alight on the line at Lake Street in the early hours of Monday.
District commander Superintendent David Moore said: “I would appeal to parents and those within the local community to exert their influence to bring this senseless behaviour to an end.”