Facebook has taken down a government advertising campaign which was accused of targeting voters in marginal general election constituencies.
The social media firm said the ads “were not correctly labelled” and did not include the obligatory disclaimer.
Each of the ads in the campaign, first reported by HuffPost UK, said the government was investing “up to £25m” in a named town.
One Labour MP said it was an “outrageous” use of public money.
The “MyTown” campaign promoted the government’s £3.6bn Towns Fund in several key general election battlegrounds, such as Northampton, Milton Keynes and Mansfield.
Each of these contain a marginal constituency, one where there were fewer than 2,000 votes separating the top two candidates in the last general election or parliamentary by-election.
Parliament has not yet been dissolved and the civil service has not yet entered the pre-election period, known as “purdah”, where it is barred from making major announcements that might influence the outcome of the vote.
But the ads went live on Tuesday, the same day Boris Johnson secured support for an early general election on 12 December.
Facebook said the taxpayer-funded ads “were not correctly labelled” as being about “social issues, elections or politics”, in line with its voluntary system to make social and political advertising more transparent.
A spokesman said: “Ads about social issues, elections or politics that appear on our platforms should include a disclaimer provided by advertisers.”
It comes as Facebook comes under pressure over its policies on fact-checking political advertising and as rival social media giant Twitter banned political adverts altogether.
Labour MP Ian Lucas wrote to Cabinet Office minister Michael Gove objecting to the campaign, saying the targeted areas appeared to be selected for political reasons.
“It would be an insult to our intelligence to say that this isn’t public money being used for political purposes. It clearly is,” he told HuffPost UK, calling the campaign “outrageous”.
A government spokesman told the BBC that the posts were published before the election was announced.
“All towns selected were chosen according to the same selection methodology, including analysis of deprivation, exposure to Brexit, productivity, economy resilience and investment opportunities,” he said.