WASHINGTON » The Obama administration official assembling the new federal agency overseeing credit cards, mortgages and other financial products is rebuffing banking industry claims that the agency is too powerful and lacks accountability.

Elizabeth Warren, who is putting together the Consumer Financial Protection Bureau, is also giving little ground against Republicans who say she’s played an inappropriate role as federal agencies and states try pressuring big U.S. banks to overhaul how they modify mortgages and handle foreclosures.

The Harvard law professor and longtime consumer advocate was testifying Wednesday before members of the House Financial Services Committee. Top Republicans on the panel and their business allies have complained that the bureau — which opens its doors July 21 — has unfettered power to clamp down on financial instruments it considers unfair.

"Americans are looking for an honest marketplace," Warren said in her prepared testimony, adding, "Today, few of us seriously believe that we have the marketplace that American families deserve."

The bureau was created by the financial markets overhaul law enacted last summer by President Barack Obama and congressional Democrats.