Petrol bombs have been thrown at police officers during disturbances in Lurgan, County Armagh, and Londonderry.
Two officers were hurt in what police described as “minor public disorder” in Kilwilkie, Lurgan, on Monday afternoon. They were not seriously injured.
In Derry, police officers escaped injury when seven petrol bombs were thrown at them in Iniscarn Crescent at about 14:30 BST on Monday.
The attack was close to the scene of a dissident republican commemoration.
The officers were on duty near Derry City Cemetery, where men in paramilitary-style uniforms took part in a ceremony to mark the centenary of the 1916 Easter Rising.
The Lurgan disturbances led to disruption on the main Belfast to Dublin railway line, which passes through the town.
It is believed that a police vehicle was surrounded for a short time on Monday afternoon by a crowd of people near the Kilwilkie estate.
There were also reports that some of the crowd attempted to place burning bins on a nearby railway crossing at Lake Street.
Northern Ireland Railways organised buses to transport train passengers to stations between Lisburn and Portadown.
Cross-border rail services were also disrupted, with passengers bussed between Belfast and Newry.
The PSNI’s District Commander in Armagh, Banbridge and Craigavon, Supt David Moore, said: “Police have arrested two youths, both aged 15, for a range of offences including riotous behaviour and criminal damage.
“I would appeal to parents and those within the local community to exert their influence to bring this senseless behaviour to an end.”
The Lurgan arrests on Monday afternoon followed overnight trouble at the same locations.
Petrol bombs were thrown at officers and a van was hijacked and set on fire at the Lake Street railway junction shortly before 04:30 BST,
There were no reports of any injuries.
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