Federal Reserve Bank of Boston President Eric Rosengren said midsize cities in the region will be a key source of economic growth and deserve more attention from policy makers.

Cities with populations between 75,000 and 200,000 should get increased attention because they haven’t experienced “the same degree of economic vibrancy” as the Boston area, Rosengren said Monday in remarks prepared for delivery in Lawrence, Massachusetts.

Midsize cities often serve as entry points for immigrants and the average age of their population is younger than other areas of New England, he said.

“Their manufacturing base has shrunk, and many have yet to replace lost jobs with new and innovative sectors,” Rosengren said.

“As more middle-class families have moved away, these cities face greater challenges in helping their residents acquire the skills and job market opportunities they need to escape from poverty.”