Some members of the Starbucks workers’ union that represents more than 10,000 baristas walked off their jobs in multiple US cities on Friday, citing unresolved issues over wages, staffing and schedules.

The five-day strike, which began on Friday and closed Starbucks cafes in Los Angeles, Chicago and Seattle, will expand to Columbus, Denver and Pittsburgh through Saturday, the union said in a statement.

This is the latest in a series of labour actions that have picked up pace across service industries following a period when workers at manufacturers in the automotive, aerospace and rail industries won substantial concessions from employers.

At Starbucks, the Workers United union, which represents employees at 525 stores across the US, said late on Thursday that walkouts would escalate daily and could reach “hundreds of stores” nationwide by Christmas Eve.

“It’s estimated that 10 stores out of 10,000 company-operated stores did not open today (Friday),” Starbucks said, adding that there was no significant impact to store operations.

Around 20 people joined a picket line at a Starbucks location on Chicago’s north side, buffeted by snow and wind, but cheering in response to the honking horns of passing cars. A few confused customers tried to walk into the closed store before strikers began chanting, but union member Shep Searl said the reaction had been mostly positive.