Ulster Rugby have been forced to apologise after a photograph showing two of their Irish international players with their bodies and faces covered with black make-up appeared on a social media site.

The photograph was posted on the Twitter profile of Irish international Paddy Jackson and also featured fellow Ulster and Ireland player Chris Henry.

They were apparently posing as members of the Ethiopian Olympic team.

Paddy Jackson appeared to have a chain around his neck and hands.

Ulster Rugby in a statement said they apologised unreservedly for any offence caused.

They said the photograph showed the players at an Olympic-themed fancy dress party two years ago.

They said it was not the players' intention to cause any upset and the photograph had been removed.

The African and Caribean Support Organisation in Northern Ireland described the photo as deeply offensive.

Joseph Ricketts from ACSONI said he was shocked an appalled by the irresponsible behaviour.

He said: "It's worse than bad taste. One of the characters was seen with a chain around the neck, which mimics the most awful period in history for black people." 

It has also emerged that all five people in the photograph were associated with Ulster Rugby.

Included along with Paddy Jackson and Chris Henry were Irish international Andrew Trimble, Ulster player Michael Allen, and former squad member Paddy McAllister.