Facebook has said it's found Russian accounts spent less than $1 on just three ads which reached about 200 people, as part of the Kremlin's efforts to interfere with the 2016 EU referendum.
In a letter to the UK electoral commission on Wednesday, Facebook said the same Russian accounts which had reached tens of millions of Americans during the 2016 presidential election had spent just a "small amount of money" trying to interfere with Brexit.
“Further to your request, we have examined whether any of the identified Internet Research Agency (IRA) pages or account profiles funded advertisements to audiences in the United Kingdom during the regulated period for the EU Referendum," read the letter.
"We have determined that these accounts associated with the IRA spent a small amount of money ($0.97) on advertisements that delivered to UK audiences during that time.
"This amount resulted in three advertisements (each of which were also targeted to US audiences and concerned immigration, not the EU referendum) delivering approximately 200 impressions to UK viewers over four days in May 2016.”
Facebook looked at only the 470 accounts linked to the Internet Research Agency, which had been identified by US intelligence services as working as part of Russia's efforts to interfere in last year's US presidential election.
During the US election, the accounts reportedly produced more than 80,000 posts which reached more than 126 million people.
BuzzFeed News understands Facebook will not widen the scope of its investigation, unless new information appears which identifies other Russian-linked accounts – for example from security agencies.
Facebook also didn't provide images, or detailed information about the three ads to the electoral commission.
The information about the three advertisements was also given to the parliament's department for media, culture and sport select committee, which is currently undertaking its own probe into Russian interference in the 2016 referendum and 2017 election.
The head of the Commons committee Damian Collins reacted on Twitter to the Facebook news on Wednesday afternoon. He said Facebook's efforts weren't good enough.
My response to @facebook letter to @ElectoralCommUK today 1) Facebook responded only with regards to funded adverti… https://t.co/X5SGqMIoJ0
2) It would appear that no work has been done by Facebook to look for other fake accounts and pages that could be l… https://t.co/q5W9Yl87Nm
3) Facebook conducted research to identify 10,000s of fake pages and accounts that were active during the French Pr… https://t.co/YSde7LC4vY
4) Are we to believe that Russian backed targeting of voters through social media with fake news was limited only t… https://t.co/D2Lf7KmsCQ
5) I've met with Facebook today and again asked them for a full response to my letter sent on behalf of @CommonsCMS… https://t.co/H4aiBbhfnV
Other US-based companies have also been asked to find out what Russian-linked interference around the time of the EU referendum by the twin investigations, with Twitter handing over evidence to the Electoral Commission last Friday.