Thousands of Verizon Communications Inc. workers are on strike from Massachusetts to Washington, D.C., over labor issues.

Dozens of people wearing red shirts and carrying signs have gathered outside Verizon's headquarters in New York City on Sunday. They're carrying signs saying they're "on strike for middle-class jobs."

The company is asking for changes in their contract including employee contributions to health care.

The 45,000 workers went on strike after their contract expired at midnight Saturday. That contract covers the company's division that oversees landlines and Internet networks.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.

Forty-five thousand Verizon Communications Inc. workers from Massachusetts to Washington, D.C., went on strike Sunday after negotiations fizzled over a new labor contract for more than a fifth of the company's work force.

Verizon is the nation's largest wireless carrier, but the contract that expired at midnight Saturday covers workers in the company's wireline division, which includes landline operations, services for businesses and governments and long-haul wholesale traffic.

Talks in Philadelphia and New York stalled Saturday night after Verizon continued to demand more than 100 concessions from workers regarding health care, pensions and work rules, said the Communications Workers of America.

CWA workers picketed at Verizon headquarters in New York City on Sunday morning, wearing red and holding signs with messages including "CWA on strike for middle-class jobs."

Mark C. Reed, Verizon's executive vice president of human resources, called the outcome of the unions' actions "regrettable" for customers and employees.

"We will continue to do our part to reach a new contract that reflects today's economic realities in our wireline business and addresses the needs of all parties," he said in a statement.

Workers covered by the expired contract include 10,000 represented by the International Brotherhood of Electrical Workers, who serve as telephone and repair technicians, customer service representatives, operators and more. Contract negotiations began June 22.

"Even at the 11th hour, as contracts were set to expire, Verizon continued to seek to strip away 50 years of collective bargaining gains for middle-class workers and their families," CWA said in a statement Sunday.

New York-based Verizon has 196,000 workers; 135,000 are non-union.

The CWA said the concessions are unjustified and harsh, given that Verizon is highly profitable _ the company's revenue rose 2.8 percent to $27.5 billion in the second quarter. Its growth was largely attributed to its wireless business.

But Verizon said its wireline business has been in decline for more than a decade as more people switch to using cellphones exclusively. It had 25 million landlines at the end of the second quarter, down from 26 million at the end of 2010. It has been selling off some of its landlines to other phone companies.

The company is asking for changes in the contract to strengthen the unit. It said union employees contribute nothing to their health care premiums.

Verizon activated a contingency plan to ensure customers experienced "limited disruption in service" for the length of the strike.

"Tens of thousands of Verizon managers and other personnel have been trained to step in and perform emergency work assignments," Verizon spokesman Rich Young said.

Lowell McAdam, the former head of Verizon Wireless, became CEO of Verizon Communications Inc. on Aug. 1, replacing Ivan Seidenberg. Seidenberg, the longtime CEO, remains chairman of the company.