The vote, which was expected, comes after 17,000 additional workers in AT&T’s phone, Internet, and cable services in Nevada and California also approved a strike authorization last month. They have been working without a contract since April.

But despite the strike authorization votes—a common tactic to increase pressure on management during labor negotiations—AT&T (T) said it was still seeking to find common ground with its workers. Unlike some of its peers, AT&T has had a long run of labor peace with its workers and their main union, the Communications Workers of America (CWA).

While Verizon (VZ) saw some 40,000 workers go out on strike for seven weeks last year, AT&T’s last strike was almost five years ago, and lasted only two days.

“We’re continuing to bargain with the union and we’re committed to reaching a fair agreement that will allow us to continue to provide solid union-represented careers with competitive wages and benefits,” an AT&T spokesman told Fortune, noting that the strike authorization vote was a routine tactic. “We’re confident an agreement will be reached.”

Workers are concerned that AT&T’s initial offers seek to make them pay more for healthcare, eliminate pension benefits for new hires, and reduce their number of sick days. They are planning some three dozen rallies over the next two days at AT&T locations around the country from San Francisco to Boston.

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“I can tell from my call center and everyone I’ve been talking to: Workers are more frustrated than AT&T realizes,” Nicole Popis, an AT&T call center worker in Illinois, said on a call with the CWA for reporters. “We are drawing a line in the sand. We’re going to do whatever it takes to win a fair contract.”

Like the Verizon workers who went out on strike, AT&T’s workers have also highlighted their employer’s outsourcing of call center jobs outside of the country. They say the carrier has moved 8,000 call center jobs since 2011 to countries including the Dominican Republic, Mexico, and the Philippines.

“The proposals AT&T [are] putting forward show AT&T just isn’t serious about maintaining good jobs in the U.S.,” Popis said. “I worry about my job constantly.”

Halting the offshoring of call center jobs was also the focus of a letter from seven Democratic senators to President Donald Trump last month. Trump’s focus so far has largely been on manufacturing jobs, as he criticized moves including Ford’s plans to build a new plant in Mexico and Carrier’s plan to move some jobs to Mexico.

But service sector jobs have also been leaving the country, the senators noted. “We are writing today to strongly encourage you to not only focus on bringing back manufacturing jobs, but service sector jobs as well; in particular customer service and call center jobs,” they wrote in the letter.

AT&T, which is under pressure from Wall Street to cut costs amid slowing growth in its wired and wireless telephone operations, said it has hired almost 20,000 workers in unionized jobs last year alone. Its workers have ratified 25 contracts in a row, covering a total of over 100,000 workers over the past two years, the company noted.

One contract deal was initially rejected last year, signaling that workers might be getting more confrontational, but a modified deal was negotiated and approved weeks later.

Union representatives said they did not have a timeline for initiating an actual strike. “We always consider a strike as a last resort,” Bob Master, legislative director for CWA’s District One, said on the call with reporters. “It’s impossible to predict. It really has to do with what happens at the bargaining table, how the members are feeling and what our leaders decide is the right thing to do.”