The Federal Communications Commission has issued citations that accuse two companies of bombarding wireless customers with millions of illegal robocalls during last year's presidential election.

Working for both the Democratic and Republican parties, the two companies placed more than 1 million artificial voice messages each without consumers' prior authorization, the FCC said Friday. The companies, Dialing Services and Democratic Dialing, also failed to provide proper identification as required by federal law, the FCC said.

"Consumers have increasingly been sounding the alarm on robocalls, rightly complaining about unwanted, intrusive cell phone calls and text messages from strangers, or worse yet computers," Michele Ellison, chief of the FCC's Enforcement Bureau, said in a statement. "These citations set the stage for significant monetary penalties if violations continue."

The companies, which allegedly placed the calls in 2011 and 2012, could face fines of up $4.8 million, $16,000 per call.

Attempts to reach the Denver-based Democratic Dialing for comment were unsuccessful as its listed phone number had been disconnected. CNET has contacted Roswell, N.M.-based Dialing Services for comment on the citation will update this report when we learn more.

FCC rules and the Communications Act prohibit robocalls and autodialed calls to mobile phones and pagers, except in the case of an emergency.

"The Bureau's investigations showed that none of the calls made by either company were for an emergency purpose," the FCC said in a statement. "When FCC staff spoke to a sampling of call recipients directly, not one of them had ever given permission to anyone to robocall them on their wireless phones."

Despite federal law prohibiting them, robocalls continue to plague wireless customers. The FCC announced a crackdown on the practice in 2012, and the Federal Trade Commission announced last year that it would pay a cash reward of $50,000 to whoever develops a solution to block robotic calling on both landlines and mobiles.