Verizon Communications Inc. (NYSE: VZ) called in hundreds of non-union employees and additional management to fill in for striking workers as the work stoppage by unions enters its tenth day.

The company said the replacements are handling customer service and network operational duties.

"We've called up hundreds of additional employees in the last few days,” said Verizon spokesman Rich Young.

"Our plan is to do what we have to do to keep our networks running. By and large, 10 days into the strike, our networks are performing solidly."

Meanwhile, the Communication Workers of America union said that more than 100,000 people have signed a petition asking the company’s chief executive to start serious negotiations with strikers.

The union claims that Verizon CEO Lowell McAdam is “trying to push Verizon workers out of the middle class.”

Much of the impasse between Verizon and unions, including the International Brotherhood of Electrical Workers, centers on $1 billion in concessions that the strikers claim the company is demanding from them.

Union officials, who say they don't want to lose their members’ free health care benefits, assert that since Verizon is a very profitable company (and has paid in excess of $258 million over the past four years to five top executives); the workers shouldn't be forced to make such sacrifices.

"We will never have an economic recovery if profitable companies like Verizon can demand huge concessions from workers,” said CWA Communications Director Candice Johnson.

“You don't build a middle class by cutting workers' wages, benefits and standard of living," she added. "That's just one reason why Verizon is becoming synonymous with VeryGreedy.”