Sen. Amy Klobuchar (D-Minn.) said the change was a “common sense safeguard” that will help prevent shocking bills.” She has supported a Federal Communications Commission recommendation that would require carriers warn users through voice and text messages that they are about to exceed monthly data and texting limits.

Apple’s move to tighten security for in-app purchases on the iPhone and iPad drew praise from lawmakers who had expressed concerns that consumers, particularly children, were being hit with accidental charges.

But legislators said tech and wireless firms need to do more to ensure that consumers are protected from vague and confusing billing.

Rep. Ed Markey (D-Mass.) said in a statement: “I am pleased that Apple has added new, clearer control settings and restrictions ... it is important that consumers are protected and mobile devices don’t become a 21st century wallet in the hands of children who may not know any better.”

“This is a positive change, but we can still do more to eliminate outrageous charges, and I look forward to working to ensure transparent billing practices for all consumers,” Klobuchar said.

She also noted the problem of “cramming,” when a third party adds unauthorized, misleading or deceptive charges to a consumer phone bill.