Nearly 50,000 Twitter accounts are being run by supporters of the dreaded Islamic State terror group, a study by a prominent US think tank has said, a worrying indicator of the outfit's reach on social media.   

Despite repeated attempts by Twitter to thwart the Islamic State's threats, propaganda and recruiting by suspending accounts linked to the group, sympathisers have maintained thousands of active accounts on the social network, the study said.

The users include a disciplined core group that sends messages frequently and understands how to maximise impact.

"Jihadists will exploit any kind of technology that will work to their advantage," said J M Berger, an expert on online extremism who was the lead author of the study, which was published by the Washington-based Brookings Institution and financed by Google Ideas.

But the Islamic State, he said, "is much more successful than other groups".  The release of the study came as Twitter, the San Francisco-based social media giant with more than 288 million active users worldwide, has moved more aggressively to suspend accounts linked to the Islamic State, The New York Times reported.