Three men were arrested and several petrol bombs were thrown at police officers during Saturday's Apprentice Boys' parade in Derry.
Police described their security operation as successful. It involved 450 police officers during the parade, which saw more than 10,000 Apprentice Boys accompanied by 150 bands march through the city centre to mark the 315th anniversary of the Relief of Derry.
Apart from isolated incidents, the parade passed off peacefully. Two of those arrested were detained for drunkenness and one was arrested for disorderly behaviour.
Chief Supt Richard Russell, who was in charge of the police operation, said his officers would be viewing security cameras to determine if retrospective arrests would be made.
"I am disappointed with the behaviour of some people who could not resist trying to provoke somebody else on the other side or who could not resist trying to provoke people. But it has happened, and we will be looking at it," he said.
"Unfortunately some of the behaviour was reprehensible, but it remains to be seen what degree of provocation there was.
"We have a considerable amount of video evidence and we will be viewing it over the next few days to determine if offences have been committed.
"In one isolated incident a group of youths from the Gobnascale area attacked my officers with petrol bombs, but there were no injuries and no damage was caused.
"When you look at the fact that this parade has been marred by serious violence in the past, today's trouble was relatively minor. We didn't have any fist fights. We did not have any blows. We did not have any petrol bombs. We did not have the firing of batons.
"So in terms of the overall scale of things, today was a success, but I am still disappointed by the fact that some people could not resist misbehaving," said Chief Supt Russell.
As part of their operation, police erected security barriers in the Diamond area of the city centre where in the past nationalist youths have clashed with Apprentice Boys.
On Saturday the area was trouble-free, except for several instances of sectarian verbal abuse.
As part of the celebrations a pageant, which included the firing of cannon and muskets, took place at Carlisle roundabout just before the main parade started. After the pageant ended, a couple walked on to Craigavon Bridge just before the parade was due to cross.
As the traditional cry of "No Surrender" went up from the ranks of the Apprentice Boys, the man who had walked on to the bridge with his partner dropped to one knee in the only puddle on the roadway, produced an engagement ring from his pocket and proposed to his girlfriend who, amid tears and hugging, accepted his proposal.