ATLANTA — Georgia's electronic touchscreen voting system is so riddled with problems that the results of the most expensive House race in U.S. history should be tossed out and a new election held, according to a lawsuit filed by a government watchdog group and six Georgia voters.

The lawsuit was filed Monday in Fulton County Superior Court by the Colorado-based Coalition for Good Governance and voters who are members of the group. It seeks to overturn the results of the June 20 runoff election between Republican Karen Handel and Democrat Jon Ossoff in Georgia's 6th Congressional District. Handel was declared the winner with 52 percent of the vote to Ossoff's 48.

The named defendants include Georgia Secretary of State Brian Kemp, members of the State Election Board, local election officials in Fulton, Cobb and DeKalb counties and the Center for Election Systems at Kennesaw State University.

The lawsuit claims Georgia's touchscreen voting system has severe security problems, lacks verifiable paper ballots and cannot be legally used for elections.

A judge in June threw out a related lawsuit earlier that attempted to force Georgia to use paper ballots.

The new lawsuit comes weeks after the publication of a classified National Security Agency report describing a sophisticated scheme, allegedly by Russian military intelligence, to infiltrate local U.S. elections systems using phishing emails.

The suit cites the work of private cybersecurity researcher Logan Lamb, who discovered last August that a misconfigured server had left Georgia's 6.7 million voter records and other sensitive files exposed to hackers. The complaint also notes that seven months after Lamb made that discovery, another researcher was able to do the same.

A spokeswoman for Kemp did not immediately respond to a request for comment Tuesday. But in a column Sunday in USA Today, Kemp blamed the news media for developing "false narratives about Russian hacking and potential vulnerabilities in the system. The prevailing plot line is that states like Georgia can't provide suitable security for elections."

Kemp asserted that states are doing enough to keep elections secure, and he said, "Anything to the contrary is fake news."

Marilyn Marks, executive director of the Coalition for Good Governance, said the lawsuit was filed hours ahead of a deadline at midnight Monday to contest the election. She says the group does election integrity work in multiple states.