Tamara Fields, the widow of an American man killed in an ISIS attack on November 9, has sued Twitter for making it easier for the militant group to grow and spread its propaganda. According to Fields, the microblogging website knowingly let the group use its platform to disseminate its message, recruit followers and raise money. Fields has filed a complaint with the federal court in Oakland, California.

“Without Twitter, the explosive growth of Isis over the last few years into the most-feared terrorist group in the world would not have been possible,” says the complaint filed on Wednesday. According to Field, at the time of her husband Lloyd’s death, ISIS had 70,000 Twitter accounts, and posted 90 tweets a minute, The Guardian reported.

Twitter and other social media websites have increasingly come under criticism for being platforms through which terror activities are encouraged and organised. In November, messaging app Telegram cracked down on ISIS activities after its makers found that the terror group was using it extensively to communicate with sympathisers.

Twitter, too, has been tightening its rules and said it reserves the right to shut down accounts engaged in hate speech and other dangerous activities. However, most platforms have maintained that they cannot be held responsible for how people use their services. Experts said this is the first time the United States' anti-terrorism law is being used to petition against a communications portal, and that this could set a precedent.