Luxury operator Sandals Resorts is reported to be one of a number of brands to have suspended digital advertising in the UK after links to extremist websites were exposed.
The Times reports today that the Caribbean specialist halted all UK digital advertising last week while it took measures to prevent a repeat.
A Sandals advert had appeared next to a YouTube video praising al-Shabaab, the jihadist group.
Other well-known brands and organisations including Jaguar Land Rover, the University of Liverpool and Marie Curie have also withdrawn campaigns after The Times investigation.
So-called programmatic or automated advertising technology increasingly employed by advertising agencies was blamed for the ads appearing on extremist sites.
The technology tracks users around the web and serves adverts targeted at them, earning money for the agency every time it is viewed.
Other brands caught up in the probe included Waitrose, Mercedes Benz and the Victoria and Albert.
The Times says the “big-six” advertising agencies, Havas, IPG, Dentsu, Omnicom, Publicis and WPP, have denied wrongdoing.