Google, Facebook and Twitter have fallen short of their pledges to combat fake news, three months before key European elections, the European Commission said on Thursday.

The tech companies and trade bodies representing the advertising industry signed up to a voluntary code of conduct in October to tackle the spread of fake news, aiming to stave off more heavy-handed legislation.

Brussels is keen to address the threat of fake news or foreign interference during campaigning for the European Parliament elections in May and also for national elections in Belgium, Denmark, Estonia, Finland, Greece, Poland, Portugal and Ukraine in the coming months.

Europe's Security Commissioner Julian King criticised the lack of progress on cracking down on fake news made by the three companies based on their monthly reports.

‘Sadly they have fallen further behind. They need to live up to the standards we are asking of them, and that they signed up to,’ King said in a tweet.

Facebook has not provided details of its actions against political ads in January nor the number of fake accounts deleted due to malicious activities targeting the European Union, the Commission said.

The Commission also found that Google's measures on political ads were not specific enough nor did the company clarify the extent to which its actions were taken to address fake news or other reasons. It did not provide concrete evidence to show that it had carried out its policies in January, the Commission said.

The EU executive also criticised Twitter for failing to provide benchmarks to measure its progress on monitoring political ads.