Verizon CEO Lowell McAdam took a big shot at Democratic presidential candidate Bernie Sanders on Wednesday for siding with striking Verizon workers and criticizing McAdam's company.

Thousands of East Coast Verizon workers walked off the job earlier in the day after the company and the Communications Workers of America union failed to come to a compromise over months-old benefits negotiations.

In a LinkedIn post, McAdam criticized Sanders' support for the Verizon workers, which the CEO characterized as "uninformed" and "contemptible."

"I understand that rhetoric gets heated in a Presidential campaign," McAdam wrote. "I also get that big companies are an easy target for candidates looking for convenient villains for the economic distress felt by many of our citizens."

He continued:

But when rhetoric becomes disconnected from reality, we've crossed a dangerous line. We deserve better from people aspiring to be President. At the very least, we should demand that candidates base their arguments on the facts even when they don't fit their campaign narratives.

McAdam also rejected some of Sanders' claims about the company, including that it doesn't pay its fair share in taxes and that it outsources jobs overseas.

He wrote:

Verizon is one of the top 3 capital investors in all corporate America. Our investment has built wireless and fiber networks that deliver high-quality services, create high-tech jobs and form the infrastructure for the innovation economy of the 21st century.

"I challenge Sen. Sanders to show me a company that's done more to invest in America than Verizon," he added.

Later Wednesday afternoon, Sanders fired back in a tweet.

The senator had joined a picket line of CWA workers in New York City and slammed both Verizon and McAdams for tussling over pension and benefits packages while the CEO takes home millions. The CWA endorsed Sanders' campaign.

"They want to give their CEO $20 million a year in compensation," Sanders said Wednesday. "They want to avoid paying federal income taxes. In other words, this is just another major American corporation trying to destroy the lives of working Americans."

This isn't the first time Sanders has campaigned on behalf of CWA workers.

In a CWA picket line in Midtown Manhattan in October, Sanders accused Verizon of mistreating its union workers by providing lackluster benefit packages and unfairly firing workers.

"Middle class in this country is disappearing, and what Verizon is doing to their workers is exactly what has got to be fought if we're going to rebuild the American middle class," Sanders said at the time.

"All over this country, Verizon is a metaphor. You've got corporate America making huge profits, their CEOs getting huge compensation packages. And then with all of their money, what they do is hire lawyers in order to make it harder for workers to survive in this country."