LOYALISTS accused "republicans" attending a party in Ardoyne, north Belfast, of slashing banners at their protest camp at nearby Twaddell Avenue.
About 10 banners pledging support for the protest were destroyed shortly before 9am yesterday.
Loyalists said two women were in the protest camp at the time.
Loyalists have protested at the site, on the junction of Twaddell and Crumlin Road, since the Parades Commission banned the Orange Order from passing the flashpoint Ardoyne shopfronts on the Twelfth of July.
Policing the protest and nightly parades costs about £50,000 per day.
Police said they were investigating the vandalism and a suspected sectarian assault on a Protestant man in the upper Ardoyne area at about 4.30am yesterday.
The man was pushed to the ground and attacked by two men who used abusive, sectarian language.
North Belfast DUP MP Nigel Dodds claimed republicans were trying to raise tensions at the interface and called for an increase in police resources in the area.
"These two sectarian attacks represent a clear attempt by certain republicans to increase tension and fears at interface communities," he said.
"Those responsible are enemies of peace and good relations.
"The cowardly and unprovoked attack on a Protestant man making his way home was followed by an act of sectarian vandalism against the civil rights camp at Twaddell.
"There were two women present in the civil rights camp at the time of the knife attack and whilst they were not directly threatened it will have been a terrifying incident for them, particularly as there was no police presence at the time.
"These premeditated sectarian attacks will be condemned by all right-thinking people and must be condemned from across the political spectrum."
Loyalists have said the protest was manned throughout the festive period and that protesters ate Christmas dinner in a caravan at the camp on Christmas Day.