BERLIN — Neelie Kroes, the European commissioner who was the scourge of American tech companies like Oracle, Microsoft and Intel, urged European Union lawmakers Thursday to abolish cellphone roaming charges.

Ms. Kroes, the European commissioner for digital policies, told members of the European Parliament’s Internal Market and Consumer Protection Committee, “I want you to be able to go back to your constituents and say that you were able to end mobile roaming costs.”

The speech was the latest effort by Ms. Kroes, a Dutch economist and former European Union antitrust chief, to fundamentally redefine the rules of the union’s telecommunications market. In theory, the market is a single economic zone. But in reality, it is a patchwork of 27 national markets where operators charge people fees whenever they cross a border with their smartphones.

Because competition has made basic mobile phone service relatively inexpensive in Europe compared with other developed countries, the roaming fees are a profitable part of network operators’ businesses. As a result, the European Parliament is expected to face heavy lobbying from the telecommunications industry against the proposal.