Roughly 40,000 Verizon workers went on strike Wednesday morning after failing to ink a new contract with the company.

The strike -- the largest of its kind in the U.S. in five years -- stretches down the East Coast, from Massachusetts to Virginia, and involves mostly Verizon technicians and customer service representatives.

The employees are represented by the Communications Workers of America and the International Brotherhood of Electrical Workers unions. They have been working without a contract since August.

The two sides have been at the bargaining table for the past 10 months. Earlier this week, there were still a handful of outstanding issues that needed to be settled. According to CWA, the company was insisting that there not be layoff protections for employees hired after 2003, and that technicians be able to work up to two months away from home. It isn't clear exactly which wedge issues remained once the strike deadline passed early Wednesday.

In a statement, CWA said the company was "refusing to give up demands on offshoring jobs and other devastating cuts."

Verizon said in a statement that it had made "good faith efforts" at the table and offered wage increases, but "union leaders decided to call a strike rather than sit down and work on the issues that need to be resolved." The company had contingency plans in place ever since the strike plans were announced, with nonunion replacement workers to fill those jobs.

"[U]nion leaders have their own agenda rooted in the past and are ignoring today’s digital realities," said Marc Reed, the chief administrative officer for Verizon, which owns The Huffington Post.

Verizon criticized the unions for not agreeing to have the federal government mediate the dispute. CWA said the issue of mediation was "a distraction from the real problem: Verizon's corporate greed."

The unions and Verizon have a long history of hard-nosed negotiations. The last strike of comparable size involved the same parties, when Verizon workers walked off the job in 2011. It lasted roughly two weeks.

This time around, the strike has an added political element that could give the unions some leverage. The presidential primaries are headed to New York, one of the states most affected by the strike. If the work stoppage continues, expect more candidates to call on the sides to reach an agreement.

Sen. Bernie Sanders of Vermont, competing with former Secretary of State Hillary Clinton for the Democratic nomination, has already voiced his support for the striking workers and made the issue part of his stump speech. The candidate, who was endorsed by CWA, joined a picket line in New York on Wednesday, delivering a sidewalk speech to hundreds. He blasted Verizon as "another major American corporation trying to destroy the lives of working Americans."

Clinton also issued a strong statement in support of the striking workers. The former New York senator on Wednesday said Verizon "should come back to the bargaining table" and "keep good-paying jobs with real job security" in New York. "Instead," Clinton said, "Verizon wants to outsource more and more jobs. That would mean walking away from workers who have been part of their family and our communities for years."

This story will be updated throughout the day.