Homes have been boarded up at a number of huge bonfire sites in the North amid concerns around safety and risk to property.
Fires will be lit in loyalist areas across the region tonight to usher in the main date in the Protestant loyal order parading season - the "Twelfth of July".
Some of the unregulated structures have been erected in built-up areas near homes and other properties.
Contractors in Belfast spent most of this morning boarding up windows at a number of the sites, including Ravenscroft Avenue and Cregagh in the east of the city and Lanark Way in the north.
The traditional "Eleventh Night" fires mark the start of commemorations of Protestant King William of Orange's victory over Catholic King James II at the Battle of the Boyne in Ireland in 1690.
The towering bonfires, most built with stacks of wooden pallets, will draw thousands of onlookers - but they are often the source of controversy.
This year has been no different, with Belfast City Council securing a court order to prevent further construction on four bonfires in the east of the city amid safety concerns.
Masked loyalists appeared to defy that order at one of the sites on Monday.
Last year, a number of terraced homes next to the Hopewell Square bonfire in Belfast's Shankill Road were badly damaged when a blaze broke out on the roofs. It was caused by hot embers blown on the wind.
Advocates of the bonfires portray them as a family-friendly, spectacular celebration of loyalist/Protestant culture.
Their detractors claim they are potentially dangerous, environmentally damaging, magnets for anti-social behaviour and alienating to nationalists.
In recent years, bonfire builders have faced criticism after items linked to the nationalist/republican tradition - such as Irish flags and posters and effigies of high-profile politicians - have been placed on the top of some of the fires and torched.
John Finucane, a Sinn Fein candidate in the general election, said he contacted police after learning that some of his campaign posters had been attached to a bonfire.
The solicitor, son of loyalist murder victim Pat Finucane, tweeted a picture of the bonfire this morning.
"My posters have been placed on top of a bonfire," he wrote.
"I have reported this hate crime & theft to PSNI to allow them to act urgently."
My posters have been placed on top of a bonfire. I have reported this hate crime & theft to PSNI to allow them to act urgently. pic.twitter.com/Qu9WuD0SeZ— John Finucane (@johnfinucane) July 11, 2017
The bonfires will burn ahead of Wednesday's Twelfth of July commemorations.
One of the biggest bonfires ignited prematurely, with firefighters working through the early hours of Tuesday to extinguish the blaze in Carrickfergus.
While the vast majority of the almost 600 Protestant loyal order parades on the Twelfth are free of trouble each year, the threat of disorder at a small number of flashpoints always has the potential to mar the day.
There is cautious optimism this year's Twelfth will pass off without major incident.
Orangemen and nationalist residents at the most contentious parade - at Woodvale/Ardoyne in north Belfast - have struck a deal that aims to reduce tensions in the area on Wednesday.