EAST HARTFORD, Conn. (AP) — About 3,000 labor union members went on strike early Monday at jet engine maker Pratt & Whitney in Connecticut, as negotiations over wages, retirement benefits and job security broke down.

Members of the International Association of Machinists and Aerospace Workers were picketing at manufacturing locations in East Hartford and Middletown, after about 77% of nearly 2,100 union members voted to approve their first strike since 2001, union officials said. Their contract expired late Sunday.

“Pratt and Whitney is a powerhouse in military and commercial aerospace products because our membership makes it so,” David Sullivan, the union’s eastern territory vice president, said in a statement. ”This offer does not address the membership concerns, and the membership made their decision — we will continue to fight for a fair contract.”

The company, a subsidiary of Arlington, Virginia-based RTX Corp., called its latest wage and retirement proposal competitive, and said its workforce is among the most highly compensated in the region and industry.

“Our message to union leaders throughout this thoughtful process has been simple: higher pay, better retirement savings, more days off and more flexibility,” the company said in a statement. “We have no immediate plans to resume negotiations at this time and we have contingency plans in place to maintain operations and to meet our customer commitments.”

The company said its latest contract proposal included an immediate 4% wage increase, followed by a 3.5% increase in 2026 and a 3% increase in 2027. It also included a $5,000 contract ratification bonus and enhanced pension and 401k plan benefits.

Pratt & Whitney makes engines for commercial and military jets, including the GTF line for Airbus commercial jets and the F135 for the military’s F-35 Lightning II fighter aircraft fleet.