Disturbances following a St Patrick's Day concert in Belfast city centre have been condemned.
Army bomb experts carried out a controlled explosion outside the bar
A police officer was injured at the Castlecourt Shopping Centre, and officers separated two crowds after a standoff in the lower Shankill area on Wednesday.
Three people were arrested following the city centre incident.
Earlier in the day, thousands of people attended a free open air concert at Belfast City Hall.
West Belfast DUP assembly member Diane Dodds said gangs coming from the concert launched unprovoked, sectarian attacks in her constituency.
"I can only say that if this is a reflection of the spirit of the people who attended the rally at the city hall, then this would not be a warm and welcoming place for people from my community," she said.
"Neither do I feel that it would be a true reflection of the spirit of St Patrick."
However, Irene Sherry from the St Patrick's Carnival Committee condemned the incidents but said the trouble was minor and had nothing to do with the celebrations.
"You cannot blame St Patrick's Carnival Committee for something that happened two hours after the concert and nowhere near our venue," she said.
"Obviously there are people who never wanted the event to take place in the first place and have continually from yesterday afternoon tried to destroy the goodness that happened yesterday in Belfast city centre."
Meanwhile, the discovery of the bomb in south Belfast led to one music event being cancelled as a pub and several houses were evacuated.
Army bomb experts carried out two controlled explosions on the device found near University Street.
Francie Mackin, owner of the Menagerie Bar, said former Pogues singer Shane MacGowan had been due to perform at the venue.
"We have been preparing ourselves for the last couple of months to provide good entertainment for people, with top names and top DJs," he said.
"For this to happen is really a blow to St Patrick's Day."
Meanwhile, in Londonderry, a man is being questioned by police after disturbances outside a bar in the city centre.
Fighting broke out at the premises on the Strand Road at midnight on Wednesday.
The trouble escalated as people left other bars in the area.
One man is being treated in hospital for serious facial wounds and a number of people suffered minor injuries.
Earlier, a number of people were treated for injuries during several fights around the city centre.
Police Land Rovers were also attacked with stones.
Police in the city described the St Patrick's celebrations as "busy" for their officers.
Police in Londonderry said there were seven arrests in the city
Overall, police in Derry said there were seven arrests for offences ranging from grievous bodily harm to disorderly behaviour and 11 reported assaults.
A PSNI spokesman said: "What was disappointing were the numbers of youths - some as young as 16 - who were roaming the city with drink taken."
He said groups of up to 100 youths had to be dispersed by police in Foyle Street and Shipquay Street following complaints early in the evening.
Police also received 13 hoax 999 calls.
"These have to be responded to and valuable resources were drawn away from the city centre where they were most needed," said the spokesman.
"Despite the large numbers who turned out in Derry for the St Patrick's Day celebrations, the level of trouble was average and could have been experienced any weekend."