The MS Society has apologised after a tweet promoting a fun run urged participants to "turn the streets of Belfast orange".
Last week, the charity tweeted to its 53,000 followers an advert for a fundraising walk it has planned to hold in the city this September.
"Let's turn the streets of Belfast orange!" it said, in a reference to the MS Society's brand colour, with a picture of supporters wearing bright orange T-shirts. However, critics pointed out it is also the colour of the Orange Order, which marches through the city every July 12.
In a statement, the MS Society apologised for the tweet, now deleted. They said: "We're sorry for any offence caused by this tweet and understand how it may have been interpreted.
"Orange is the MS Society's brand colour and this campaign was used to promote our MS fundraiser across the whole of the UK. We appreciate the sensitivities in Northern Ireland. This was an honest mistake and the advert has now been taken down."