McDonald's has apologised for a Halloween marketing campaign which promoted a dessert in Portugal with the words: "Sundae Bloody Sundae".

Axar.az reports citing foreign media.

The term Bloody Sunday is used to refer to one of the worst days of the Troubles in Northern Ireland, when 13 people were shot dead by the Army.

The adverts sparked outrage when photos were shared on social media.

McDonald's said the marketing campaign was not intended to be an "insensitive reference to any historical event".

"We sincerely apologise for any offence or distress this may have caused," a spokeswoman for McDonald's Portugal said.

She explained the "Bloody" sundae adverts were designed as a Halloween celebration but the promotion has since been cancelled.

Bloody Sunday made headlines around the world when soldiers opened fire on a civil rights march in Londonderry on Sunday 30 January 1972.

A photo of the advert, with McDonald's branding, was shared online by an Irish Twitter user, who commented: "Portugal is cancelled."