MACUNGIE, Pa. (AP) – Mack Truck workers are walking picket lines after their union launched a strike at plants in three states.

The United Automobile Workers Union Local 677 workers began picketing Sunday morning at the Mack Truck cab and vehicle assembly plant and Lehigh Valley Logistics Center outside Allentown in Macungie, Pennsylvania.

The company said the strike involves about 3,500 employees at facilities in Pennsylvania, Maryland and Florida.

The union says many issues are unresolved, including wages, job security and pension and health benefits.

Mack Trucks President Martin Weissburg says he’s “surprised and disappointed” that the union decided to walk out “rather than to allow our employees to keep building trucks and engines while the parties continued to negotiate.”

The action comes amid a weekslong United Automobile Workers strike at General Motors plants.

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