WASHINGTON — Lawmakers leveled stinging criticism and sharp questions at Big Tech executives on Tuesday, attacking Amazon, Apple, Facebook and Google for their market power, their perceived bias as gatekeepers of communication and Facebook’s ambitions to reshape the financial industry.

The criticisms came at three hearings on Capitol Hill that showcased Washington’s widening range of concerns with Silicon Valley. Lawmakers from both parties, including Senator Ted Cruz, Republican of Texas who oversees a subcommittee on the Constitution, and Representative David N. Cicilline, Democrat of Rhode Island who leads a subcommittee on antitrust law, took aim at the businesses.

The executives acknowledged that technology had changed, and sometimes hurt, companies in industries like retailing, advertising, music and movies. But their companies, they said, have opened new opportunities to millions of entrepreneurs and small businesses. They insisted they faced competitors at every turn — entrenched big companies, ascendant start-ups and each other.

And consumers, they said, are big winners, benefiting from convenience, lower prices and new products and services.