Furniture store Habitat has apologised for causing offence after accusations it exploited unrest in Iran to drive online Twitter users to its products.
Keywords - called hashtags - such as 'Iran' and 'Mousavi' were added to its messages so people searching for those subjects would see the firm's adverts.
Users of the networking site reacted angrily and the posts were removed.
The retailer has said the use of the hashtags were "not authorised", but declined to say who was responsible.
Contributors to Twitter posted messages claiming Habitat should be "ashamed" and saying it was "piggy-backing" on the political situation in Iran.
One of the controversial messages - called tweets - which appeared before being removed by Habitat, read: HabitatUK: #MOUSAVI Join the database for free to win a £1,000 gift card.
From the BBC.