Twitter has been accused of failing to provide straight answers to MPs investigating Russian influence on the Brexit vote.
The tech company and Facebook were first given a ticking off late last year over "inadequate" responses to a fake news inquiry by the digital, culture, media and sport select committee.
Twitter has now responded, telling committee chair Damian Collins that one per cent of 13,500 accounts identified as bots active only during the Brexit vote by a group of researchers were registered to Russia.
And nearly half of the bot accounts were removed under spam rules before the study took place in October 2017, Twitter said in a letter. The tech firm concluded that there was little evidence of a link between the bots and Russia.
Collins said the committee was not satisfied with the response.
"I'm afraid that the failure to obtain straight answers to these questions, whatever they might be, is simply increasing concerns about these issues, rather than reassuring people," he said.
The committee was left with "outstanding questions" that remain unanswered as well as further ones in light of the response, Collins said, adding that he expected a further response before the company and other technology firms give evidence to the committee on 8 February.
That evidence session will be held in the US - a first in select committee history - where it will grill tech company representatives on home turf.
Facebook responded to MPs' initial concerns last week, saying that it would expand its own investigation into the matter.