(New throughout with introduction of bills)
WASHINGTON, Oct 19 (Reuters) - U.S. lawmakers, alarmed over hackers' use of the internet to influence last year's election, introduced legislation on Thursday to extend the rules that apply to political advertising on television and radio to social media like Facebook Inc.
Democratic Senators Amy Klobuchar and Mark Warner and Republican John McCain introduced the "Honest Ads Act," which would amend existing election law covering television and radio outlets to impose those rules to paid internet and digital advertisements on platforms like Facebook, Twitter Inc and Alphabet Inc's Google.
"Our laws have failed to keep up with evolving technology and the capabilities of our foreign adversaries," Klobuchar told a news conference.
The measure would also require digital platforms with at least 50 million monthly views to maintain a public file of all electioneering communications purchased by anyone spending more than $500.
And it would require online platforms to make "all reasonable efforts" to ensure that foreign individuals and entities are not buying political advertisements to influence the U.S. electorate.
Companion legislation was introduced in the House of Representatives by Republican Representative Mike Coffman and Democrat Derek Kilmer.
Social media companies have become an increasing focus of congressional investigations into allegations that Russia sought to meddle in the 2016 U.S. election on behalf of Republican candidate Donald Trump, something now-President Trump and Moscow deny.
Warner said $150,000 of ads paid for in rubles may be only the "tip of the iceberg" in terms of how many political advertisements were bought by foreign firms. He said advertisements could have been purchased using dollars, euros or pounds.
He and Klobuchar acknowledged that the companies have resisted the legislation but said, "It's our hope that the social media companies and platform companies will work with us."
Separately, Facebook and Twitter said Thursday they would send their general counsels to testify Nov. 1 before the Senate and House Intelligence Committees.
An executive from Google also is expected to appear at the public hearings, although the company has not yet said who will testify. A Google spokeswoman said on Thursday she had no update.
General counsel Colin Stretch will be the Facebook representative to testify before both committees, company spokesman Andy Stone said. The company's high-profile Chief Executive Officer Mark Zuckerberg and Chief Operating Officer Sheryl Sandberg will not appear.
A Twitter spokeswoman said Acting General Counsel Sean Edgett will represent the microblogging site. (Additional reporting by David Ingram in San Francisco and Doina Chiacu in Washington; Editing by Jeffrey Benkoe and Cynthia Osterman)