WASHINGTON (Reuters) - The Justice Department has closed an antitrust investigation into a trade group that includes Verizon and AT&T among its members and which had been criticized for making it harder for consumers to switch carriers.

FILE PHOTO: A general view of the Department of Justice building is seen ahead of the release of the Special Counsel Robert Mueller's report in Washington, U.S., April 18, 2019. REUTERS/Amr Alfiky

In a letter to the GSM Association, which sets standards on eSIM mobile technology and includes the four major U.S. carriers, the Justice Department said it was pleased that the group “is ready to use its standard-setting process to create a more consumer-friendly eSIM standard.”

The technology called eSIM allows consumers to switch wireless providers without having to insert a new physical SIM card, an identifying microchip. That makes it easier to compare wireless networks and easily select a new service when desired.

Previously, there had been allegations that the standard was set in a way that made it harder to switch carriers and to make it harder for new wireless companies to enter the market.

The Justice Department did not say in its letters which carriers were included in its probe. In April 2018, Reuters and others reported that the department was probing alleged coordination by AT&T Inc, Verizon Communications as well as the trade group. T-Mobile and Sprint are also part of the organization.

Verizon, T-Mobile and Sprint did not respond to requests for comment. AT&T declined comment.

GSMA said in a statement that the department had looked at “millions of documents.” “Its Business Review Letter is conclusive that the agency found no violation of antitrust laws,” the trade group said.

In its letter, the Justice Department said that it was closing the probe because the GSMA agreed to change some of its procedures.

“As a result of that investigation, the Department developed significant concerns that GSMA’s process was deeply flawed and enabled competitors to coordinate anticompetitively,” the department said, without naming the competitors.

The department further said it had “no present intention” to pursue an antitrust enforcement action against GSMA’s conduct.

Gigi Sohn, a consumer advocate and telecommunications expert, said the letter was a “slap on the wrist” because the Justice Department Antitrust Division did nothing more than force a change in anti-competitive behavior.