BELFAST (Reuters) - Annual parades in Northern Ireland that frequently trigger sectarian violence passed peacefully on Wednesday with little sign the province’s political crisis is increasing tensions on the streets.

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A power-sharing coalition between pro-British Protestant unionists and Irish Catholic nationalists collapsed in January and the protracted political impasse raised fears that inter-community relations might deteriorate.

Traditional July and August marches are seen as a barometer of those relations and Wednesday’s were among the most peaceful since a 1998 peace deal ended three decades of sectarian fighting in which 3,600 people died.

Police Service of Northern Ireland Assistant Chief Constable Alan Todd called it “the most peaceful Twelfth of July for some years and a model for years to come.”

Tens of thousands of mainly Protestant unionists, some wearing orange sashes and bowler hats began marching across the province early on Wednesday to the accompaniment of pipe bands.

The marches mark the 1690 victory by Protestant King William of Orange over Catholic King James at the Battle of the Boyne, which secured Protestant ascendancy in Britain and Ireland.

The sort of angry protests by nationalists, who want Northern Ireland merged with the Republic of Ireland, that frequently greet the marches, were nowhere to be seen, though the worst trouble tends to occur late in the evening.

A morning unionist march past an Irish nationalist estate in North Belfast that has often been the scene of violence passed off without incident. Marchers agreed to cancel the evening leg, which has frequently caused street clashes.

The grand secretary of the Orange Order, which organizes the marches, said there appeared to be less tension this year.

“We took a deliberate decision last year not to issue statements about parades so that would not increase tensions. I believe that paid off,” Mervyn Gibson told the BBC.

Police said they had launched an investigation after some unionists overnight burned a replica coffin bearing the image of Martin McGuinness, former leader of the nationalist Sinn Fein party in Northern Ireland, who died in March.

The coffin was burned on a large bonfire in Belfast along with Irish flags and Sinn Fein election posters.

Sinn Fein national chairman Declan Kearney described the burning of the coffin as a “particularly sickening manifestation of hate” and called on unionist politicians to condemn it.

Some commentators linked the collapse of talks between Sinn Fein and the Democratic Unionist Party earlier this month to a reluctance to risk angering supporters ahead of July 12 by making major concessions.

Talks between the parties on resurrecting the power-sharing government are to resume later in the summer.

The governments of Britain and Ireland have warned that failing to forge a new deal would have “profound and serious” implications and limit Northern Irish influence in Britain’s negotiations to leave the European Union. However, no one is forecasting a relapse into serious sectarian violence.