A controversial bonfire that was built in a leisure centre car park in east Belfast was lit as part of the Eleventh Night celebrations.
It was one of hundreds set on fire across Northern Ireland on Thursday on the eve of the Twelfth of July marches.
Earlier in the day Belfast City Council gave up on its efforts to remove the bonfire at Avoniel Leisure Centre.
It came after a contractor that was due to remove the bonfire pulled out after graffiti threats appeared nearby.
The council wants police to investigate how details of removal contractors were leaked and appeared in the graffiti threats.
The Democratic Unionist Party's (DUP) Gavin Robinson, the MP for East Belfast, said he believed the loyalist paramilitary group the Ulster Volunteer Force (UVF) was involved in the bonfire dispute.
On Thursday morning, the council warned that anyone in the leisure centre grounds would be regarded as trespassers.
The Police Service of Northern Ireland (PSNI) said it would investigate the council's complaint about aggravated trespassing.
It also said officers would meet council representatives to discuss a complaint about the leak of contractors' details.
Police carried out searches in Avoniel on Thursday after suggestions that a suspicious object had been left in the area but nothing was found.
Speaking to the BBC's Talkback programme, Mr Robinson condemned the events surrounding the closure of the leisure centre on Sunday.
The council closed it after its entrance was barricaded by men who were behaving in a "threatening" way to staff.
"That's not, in my view, an appropriate expression of culture," said Mr Robinson.
Analysis: Mark Simpson, BBC Newsline reporter
Attention is now switching from the bonfire to the investigation into how the names of the contractors were leaked.
Although it will focus on Belfast City Hall, the question being asked by some in political circles is whether anyone in the PSNI could have leaked the names?
There is nothing to suggest they did, but given the theoretical possibility, is it appropriate that the PSNI should conduct the investigation?
He said that if people recognised bonfires were part of Northern Ireland's "cultural tapestry" then agreement was needed about where they took place and how they could be managed safely.
"Those are the sort of issues that, rather than leave them to the last minute, need to be grappled at an earlier stage by the council," he added.
Police warned on Wednesday there was a risk of "serious violence" due to UVF involvement and it "could not rule out a risk from firearms" if council workers tried to dismantle the Avoniel bonfire.
DUP councillor George Dorrian said the decision not to remove the bonfire was sensible given that no contractors were available to remove it.
Protesters said they tried to compromise with authorities but were determined that the event would go ahead on Thursday night.
Welcoming the council's decision, Robert Girvan, from a group calling itself the East Belfast Cultural Collective, which represents a number of bonfire builders, denied any paramilitary involvement.
"Unless the UVF is 70-year-old grannies and 12-year-old children, there's no UVF involvement here," Mr Girvan said.
He criticised the council's allegation of trespassing, saying that Sinn Féin and Alliance Party councillors were "denying children the use of a play park".
Controversy and protest
Tensions had been building ahead of bonfires being lit across Northern Ireland on the eve of the Twelfth of July.
It is the main date in the Protestant Orange Order marching season, commemorating the 1690 Battle of the Boyne.
Most fires are lit without major incident but some prove contentious, with the authorities having taken action in recent years on bonfires deemed unsafe and posing a threat to nearby properties.
Belfast City Council's emergency meeting on Thursday was its fourth on the bonfire issue in four days.
The bonfire at Avoniel Leisure Centre had been contentious because tyres had been placed on it to be burnt and it was built on council property without permission.
Bonfire builders voluntarily removed tyres after contractors acting for the council removed 1,800 tyres from another bonfire nearby.
Hundreds of people gathered at the Avoniel bonfire on Tuesday to protest against the council's decision to remove it.
It is estimated there were between 80 and 100 bonfires in Belfast this year, with 35 signed up to an official scheme funded by the council.
In County Armagh, a large crowd watched as another controversial bonfire was lit on Wednesday night.
The bonfire at Drumilly Green in Portadown was built close to flats, causing a housing association to advise dozens of residents to leave their homes.
Hundreds of windows were boarded up to protect them from the heat of the blaze and fire service sprayed two of the nearby blocks of flats with foam to keep them cool.
It is thought the Drumsilly Green bonfire is traditionally lit on 10 July to allow people to attend other bonfires on the Eleventh Night.