Police in Glasgow have warned troublemakers to stay away from this weekend's Republican parade.
The Republican march marks Bloody Sunday
About 300 protesters tried to clash with marchers in last year's Bloody Sunday commemoration parade.
Strathclyde Police Assistant Chief Constable Kevin Smith said the racist, sectarian and paramilitary abuse was unacceptable.
The parade by Cairde na hEireann (Friends of Ireland) is due to start at 0930 GMT on Saturday.
Parade reforms were proposed after a review by ex-police chief Sir John Orr.
Parades can be blocked if there have been offensive chants, threatening or drunken behaviour, or marchers expressing support for paramilitary organisations.
Mr Smith said police would crack down on any troublemakers who tried to replicate last year's clashes, which led to three arrests.
"Unfortunately, the parade last year was a difficult one with a significant number of counter protesters, many of whom were clearly intent on attacking and disrupting the parade," said Mr Smith.
"To be perfectly frank, many of those involved in the procession and many of those who came to protest about it did not come out with any great credit.
"Racist, sectarian and paramilitary abuse being hurled was the norm, with a number of bottles and other missiles being thrown, only adding to the difficulties."
He added: "There is a simple message here. If you come to take part in the procession or to protest, do so peacefully and lawfully."
Jim Slaven, of Cairde na hEireann, said: "We expect the march to be peaceful and we believe that all participants will conduct themselves with dignity and respect for the victims of Bloody Sunday.
"This is a very important date in the Irish community's calendar in Scotland."
A spokesman for Glasgow City Council said: "We granted permission for the event after careful consideration of our policy on public processions."
Flags and emblems
Ian Wilson, Grand Master of the Orange Lodge in Scotland, said his organisation was not involved in last year's trouble and had no intention of counter-protesting at the march.
"The parade is legal and while we are out of sympathy with the political aspirations of a Republican march, this is a democracy and they are entitled to express their view lawfully," he said.
"Counter-demonstrators are also entitled to protest but it has to be peaceful. What happened last year was a disgrace.
"I would encourage the police to be more robust in dealing with some of the paramilitary flags and emblems which were being illegally flaunted by Republican marchers last year."