Twitter shares plunged as much as 20% in pre-market trading after the social-media platform said monthly active users had fallen by 1 million in the second quarter.
The company had been under pressure to suspend users for hate speech, abusive content and the spread of misinformation.
Chief executive Jack Dorsey said: “We continue to invest in improving the health of the public conversation on Twitter,
making the service better by integrating new behavioral signals to remove spammy and suspicious accounts and continuing to prioritize the long-term health of the platform over near-term metrics.”
He added: “We also acquired Smyte, a company that specializes in spam prevention, safety, and security.”
It’s larger rival Facebook lost $120bn in market value on Thursday after it warned sales growth was slowing and cost rising as it addresses concerns about personal data usage.