Scenes of violence against police during a dissident parade in Londonderry have been condemned by politicians across Ireland.
A number of missiles were hurled by young people at a PSNI Land Rover monitoring the parade in the Creggan area of the city on Easter Monday.
The parade, organised by the Derry 1916 Commemoration Committee, started in the Central Drive area when a number of masked men in paramilitary-style dress formed a colour party carrying the Irish flag and a host of republican flags.
As the parade progressed towards the City Cemetery, the police Land Rover came under attack, with masked youths throwing petrol bombs and firing fireworks before it drove off in flames.
The parade culminated at the republican plot in the cemetery, where speeches were heard.
One speaker described the event as “respectful and dignified, paying homage to the revolutionary heroes of 1916 and all the republican dead”.
A PSNI spokesman said: “Our officers have come under attack in Creggan, with petrol bombs and other objects thrown at their vehicle while in attendance at an unnotified Easter parade.
“No injuries have been reported at this time.
“We would appeal for calm.”
Northern Ireland secretary Chris Heaton-Harris said he hoped the situation would quickly calm down.
“It is very, very disappointing that people have gone ahead with a march that has not been notified to the police,” he told the BBC.
“Hopefully it will calm down very quickly and the police can get about their business because they are there to protect all communities across Northern Ireland.”
Foyle MP Colum Eastwood said the “senseless violence” is the last thing the people of Derry want to see.
“It was wrong 25 years ago and it is wrong now,” he said.
“The saddest part of this spectacle is that young people with no memory or experience of the violence of our past are being manipulated and abused by people with no vision for the future.
“Those whipping our kids into a frenzy and sending them out to attack the police have nothing to offer the people of Derry and this city will continue to reject them.”
DUP MLA Gary Middleton tweeted: “Another clearly coordinated attack on the PSNI.
“The parade was illegal from the outset. This reckless behaviour is an attempt to cause harm not only to PSNI officers but to our communities as well. There must be swift action to bring those responsible to justice.”
Ulster Unionist leader Doug Beattie said: “Absolute wasters. Sent out to riot by men sitting in pubs acting the big lads.”
Alliance Party MLA Kellie Armstrong tweeted: “Disgraceful. The actions of some who want to drag NI back to dark days is abhorrent.”
Irish enterprise minister Simon Coveney also tweeted his support for the PSNI.
“So called dissident republicans have nothing to offer our society, north or south,” he said.
“A tiny minority of thugs seeking headlines, wanting to take Northern Ireland backwards.”
Last week, senior police warned of the potential for disorder at the event.
Assistant chief constable Bobby Singleton said the force received “strong” intelligence that dissidents were planning to launch terror attacks against officers on the bank holiday.
Police increased security measures in response to the parade.
Groups marched in west Belfast and other areas in Northern Ireland across the Easter weekend as part of an annual public marking of the anniversary of the 1916 Easter Rising against the then-British rule across the island of Ireland.
Most parades were lawful and passed without incident.
However, police are investigating a masked colour party which led a parade in Falls Road in west Belfast organised by the Irish Republican Socialist Party on Sunday.
Parade participants were issued with warnings and footage was gathered by police, who will review it as part of an investigation into potential terrorism offences.