Hacking activities appear to have increased in the run-up to the Nov. 8 US presidential polls with cybercriminals now targeting voter registration systems of more than 20 states, including Arizona and Illinois, reports AP quoting a U.S. Department of Homeland Security (DHS) official. As a result the DHS, says another source, has called for “cyber hygiene” scans of election websites even as authorities allayed fears of the poll outcome being compromised by hackers.

Officials say registration systems of Arizona and Illinois were probed without much harm done because they have "nothing to do with vote casting or counting."

Last month DHS Secretary Jeh Johnson asked state election officials to ramp up security of their polling systems, ensuring voting machines are not connected to the internet, says AP. The FBI too issued a warning after it detected “scanning activities” and spoke to Florida officials during what it described as merely an "informational call related to elections security" -- however, a source says the call was held after the probing of a local election website.

The Bureau is investigating involvement of Russian hackers.

Read full story on AP.