LONDON — British election monitors do not have a clear picture about how political actors are running their digital campaigns just days before a nationwide vote, a senior U.K. official told POLITICO.

The comments from Louise Edwards, head of regulation at the U.K.s Electoral Commission, come as campaigners ramp up spending on online ads ahead of Thursdays general election, and pressure grows on tech firms to be more transparent about how political groups use their platforms to target would-be supporters.

“We need information to carry out regulation. It isnt OK to rely on people to cooperate,” Edwards told POLITICO during a recent interview at the Electoral Commissions headquarters in central London. “You need to have a clear regulatory gateway. There needs to be proper evidence gathering techniques.”

She added that lack of transparency was making it difficult to understand what was going on in the countrys digital campaign, and that social media companies like Facebook and Google should give more access to regulators to understand how their platforms were used to woo voters.

With just days to go before the December 12 vote, traditional political parties have already spent more than £2 million since early November on targeted ads, according to official records.

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In response, Facebook said that it agreed with the Electoral Commission on the need to update the U.K.s electoral rules, and that it was doing what it could to increase transparency around political ads.

“Issues like what constitutes a political ad, who can run them and when, and what steps those who purchase political ads must take should be properly decided by Parliament and regulators,” Alex Belardinelli, a Facebook spokesman, said in a statement.

Despite social media companies creating new transparency tools to help policymakers and the general public gain better insight into online campaigns, Edwards said that her team did not have the authority to demand granular information about party-political spending online.

Instead, they typically rely on the companies public transparency tools, which offer a delayed overview of how political actors are spending money to target voters. Such tools often do not provide a complete picture of how groups are using the platform for political purposes.

“Its a step in the right direction, but there are major issues with it,” Edwards added. “Their definitions of what constitutes a political ad are different to what the electoral rules say.”

Call for a bigger stick

U.K. regulators have been calling for changes to campaigning rules for more than a year.

Both the Electoral Commission and the Information Commissioners Office, the local privacy regulator, cited political parties ongoing aggressive data-collection practices — and