Twitter (NYSE:TWTR) shares tumbled over 17 percent on Friday, after reporting an ongoing fall in monthly user numbers.

The company said that monthly users were down by one million on the previous quarter, at 335 million, and added that it expected the figure to continue to fall in the third quarter as the company continues to eliminate fake accounts.

Aside from this figure the news was positive, with the social media platform reporting a record profit of $100 million. Revenues also rose, boosted by stronger demand for advertising, with sales up 24 percent to $711 million.

Twitter boss Jack Dorsey said:

“Our second quarter results reflect the work we’re doing to ensure more people get value from Twitter every day.

“We want people to feel safe freely expressing themselves and have launched new tools to address problem behaviours that distort and distract from the public conversation.”

Shares in Twitter are currently trading down 15.58 percent at 36.25 (1445GMT).