WASHINGTON (Reuters) - Democratic senators and consumer advocates on Monday urged the Trump administration to resume an investigation into how Equifax failed to protect the personal data of millions of consumers after Reuters reported that the head of the U.S. consumer watchdog has pulled back on the existing probe.

FILE PHOTO: Credit reporting company Equifax Inc. corporate offices are pictured in Atlanta, Georgia, U.S., September 8, 2017. REUTERS/Tami Chappell/File Photo

In September, Equifax Inc said hackers had stolen personal data it collected on some 143 million Americans.

On Monday, Reuters reported that Mick Mulvaney, head of the Consumer Financial Protection Bureau (CFPB), has dialed back the investigation begun by his predecessor, Richard Cordray.

Specifically, sources said Mulvaney has held back from ordering subpoenas against Equifax - a routine step in launching a full-scale probe. Meanwhile, the CFPB has shelved plans for on-the-ground tests of how Equifax protects data, an idea backed by Cordray.

The CFPB also recently rebuffed bank regulators at the Federal Reserve, the Federal Deposit Insurance Corp and the Office of the Comptroller of the Currency when they offered to help with on-site examinations of credit bureaus, said two sources familiar with the matter.

“The (Trump) administration should get on the side of consumers and focus on making sure hacks like the #EquifaxBreach don’t happen again,” tweeted Senator Mark Warner, a Democrat.

Warner and fellow Democrat Elizabeth Warren, both members of the Senate Banking Committee, have proposed reforms that could have cost Equifax hundreds of millions of dollars in fines if they had been in place last year.

Mulvaney is leading the CFPB on a temporary basis, and the Senate will have a say on any long-term replacement.

Senator Sherrod Brown, the highest-ranking Democrat on the banking panel, said Trump should name a permanent CFPB chief now.

“The Administration needs to swiftly nominate a CFPB director who will protect consumers instead of letting well-connected corporations walk away scot-free,” Brown said in a statement.

The National Consumer Law Center, an advocate for financial protections, said the CFPB should be leading the investigation into the Equifax breach.

“With half of the U.S. population victimized, you think there’d be universal agreement that Equifax should be held accountable for its incompetence,” said attorney Chi Chi Wu.