Alphabet Inc's Google said on Monday that it had removed search ads that charged users searching for voting information large fees for voter registration or harvested their personal data.

A Google spokeswoman told Reuters that the company's misrepresentation policy barred such ads, which were found by the nonprofit watchdog Tech Transparency Project when searching for terms such as "register to vote," "vote by mail," and "where is my polling place."

Tech Transparency Project said in a report on Monday that nearly a third of the more than 600 ads generated by its Google searches took users to sites that try to charge large fees for voter registration services, extract personal data for marketing purposes, install deceptive browser extensions, or serve other misleading ads.

The report said that the first ad in a Google search for "register to vote" directed users to a site from PrivacyWall.org that charged $129 for "same-day processing" of voter registration. U.S. voters do not need to pay to register to vote.

PrivacyWall did not immediately respond to a Reuters request for comment.

A Google spokeswoman said the company did not yet know how the ads had got through its approval process, which uses a combination of automated and manual review.

"We have strict policies in place to protect users from false information about voting procedures, and when we find ads that violate our policies and present harm to users, we remove them and block advertisers from running similar ads in the future," the spokeswoman said.

"Some people may find it difficult to distinguish Google ads from other kinds of content because as of January, search ads on Google feature the same type face and color scheme as organic search results," the TTP report said.

Social media companies and online platforms, including Facebook Inc. and Twitter are under pressure to curb misinformation on their sites in the run-up to the U.S. presidential election in November.