An AT&T sign is seen outside a branch in Rolling Meadows, Illinois, U.S., October 24, 2016. REUTERS/Jim Young

(Reuters) - About 37,000 AT&T Inc T.N workers, or less than 14 percent of the company's total workforce, began a three-day strike on Friday after failing to reach an agreement with the No. 2 U.S. wireless carrier over new contracts.

This is the first time that AT&T wireless workers are on strike, which could result in closed retail stores during the weekend, according to the Communications Workers of America (CWA) union. The workers on strike are members of the CWA.

The workers are demanding wage increases that cover rising healthcare costs, job security against outsourcing, affordable healthcare and a fair scheduling policy.

Slightly over half of the workers on strike are part of the wireless segment and the rest wireline workers, including a small number of DirecTV technicians, AT&T spokesman Marty Richter told Reuters.

The CWA had said on Wednesday that wireless workers across 36 states and Washington, D.C. would walk-off their jobs if an agreement was not reached by Friday 3 p.m. ET.

Wireline workers, who work in phone, landline and cable services businesses in California, Nevada, and Connecticut, and DirecTV technicians across California and Nevada have also joined the strike. bit.ly/2riWfeB

“A strike is in no one’s best interest, and it’s baffling as to why union leadership would call one when we’re offering terms in which our employees in these contracts ... will be better off financially,” Richter said.

The groups on strike represent four different union contracts, the CWA said.

In March, about 17,000 AT&T wireline workers in California and Nevada went on strike.