The state of Washington has announced it is suing both Facebook and Google for allegedly violating state campaign finance laws. According to the lawsuit, filed by states attorney general Bob Ferguson , the two companies failed to maintain information about who bought election ads.

Unlike many US legal jurisdictions, both the state of Washington and the city of Seattle have laws in placing dating back to the 1970s that require firms selling advertising to disclose who buys political ads.

Ferguson said his office received a citizen complaint back in April that Facebook and Google had not provided this legally required information, and following an investigation, the state is now seeking penalties and an injunction against both firms for failing to disclose spending in state elections since 2013.

Both companies have faced criticism from lawmakers, transparency advocates and users over the past two years. Investigators are still looking into their role in allegedly selling political ads to Russian agents who purchased advertising to sway American voters during the 2016 US Presidential elections.

A spokesperson from Facebook said that it is looking forward to resolving the lawsuit quickly, and has recently introduced tools for people to see who is buying political ads on its platform. While Google is yet to respond, it has also pledged to create an online archive of political ads that can be freely accessed.