Social media giant Twitter pulled two flashing videos from Vine after an epilepsy group complained they are "massively dangerous" and might trigger seizures.

Epilepsy Action, a United Kingdom-based epilepsy advocacy group, said flashing bright lights and patterns are commonly reported triggers for seizures. The Vine video ads on Twitter's website, designed to promote new artists, were six-second loops of bright flashing colors.

"Your #DiscoverMusic Vines are massively dangerous to people with photosensitive epilepsy. Please take them offline now," " Epilepsy Action tweeted Friday.

Twitter responded by taking them down some 18 hours later.

"Eighty-seven people are diagnosed with epilepsy every day and that first seizure can often come out of nowhere," Epilepsy Action's deputy chief executive, Simon Wigglesworth, told the BBC. "For a huge corporation like Twitter to take that risk was irresponsible."

In 1997, an episode of the Japanese cartoon Pokemon was reportedly linked to hundreds of seizures.