The FBI has uncovered evidence that foreign hackers breached two state election databases in recent weeks, and it has warned election officials across the country to some measures to step up the security of their computer systems. The Guardian reports: The FBI warning did not identify the two states targeted by cyber intruders, but Yahoo News said sources familiar with the document said it referred to Arizona and Illinois, whose voter registration systems were penetrated. Citing a state election board official, Yahoo News said the Illinois voter registration system was shut down for 10 days in late July after hackers downloaded personal data on up to 200,000 voters. The Arizona attack was more limited and involved introducing malicious software into the voter registration system, Yahoo News quoted a state official as saying. No data was removed in that attack, the official said. US intelligence officials have become increasingly worried that hackers sponsored by Russia or other countries may attempt to disrupt the November presidential election.