Twitter is expanding its policy around control of campaigning adverts to cover this year's European Parliament elections.

The move will mean it will be possible to see details such as billing information, advertising spend and impressions per tweet for adverts endorsing a party or a candidate.

Demographic-targeting data for the ads will also be visible.

The adverts will remain indefinitely within the company's "Ads Transparency Center", and will be visible to anyone in the world, regardless of whether or not they own a Twitter account.

In a blogpost Karen White, Twitter's Director of Public Policy for Europe, said the development would provide the general public with an additional layer of insight into who is running a political campaign advert on Twitter.

"In addition to the information being shared within the Ads Transparency Center itself, we are making it clearer who is advertising European political campaign content on Twitter by including a visual label and disclaimer information on promoted content from certified accounts," she said.

"This will allow users to easily identify political campaign ads and to know who paid for them."

The further rollout of the Political Campaigning Policy and Ads Transparency Center will cover all European Union member states, India and Australia.

In order to qualify for the policy, candidates, organisations, and individuals who wish to use Twitter to advertise as part of their political campaign will first have to go through a certification process.

Once their identity has been verified and they have been deemed eligible to take part, a letter with an access code will be sent to their address to confirm they are located within the EU.

The new policy will come into force on 11 March and after that date the company says only those with certified status will be able to run political campaigning ads.

Twitter says it intends to expand this policy to country-level elections in the future.

"In addition to increased transparency around political ads, we've also formed a high-level internal elections group to lead our electoral integrity work in the region from now until polling day," Ms White said.

"Using our proprietary-built internal tools, the team will proactively protect the integrity of regional trends, support partner escalations, and identify potential threats from malicious actors."

Similar teams have been put in place by Twitter ahead of recent elections in Germany, Sweden, Mexico, the US, and Brazil.

The firm says its public policy team will engage in the coming weeks with political parties and EU member state local offices to arrange training, distribute resources and promote constructive participation in the democratic process.

Other social media firms, including Facebook, have also been working to improve their transparency around political advertising in the face of significant criticism that they have not done enough in the past to stop their platforms being used for the manipulation of voters.