Multiple banks say they are seeing evidence that Home Depot stores may be the source of a massive new batch of stolen credit and debit cards that went on sale this morning in the cybercrime underground. Home Depot says that it is working with banks and law enforcement agencies to investigate reports of suspicious activity.

Contacted by this reporter about information shared from several financial institutions, Home Depot spokesperson Paula Drake confirmed that the company is investigating.

“I can confirm we are looking into some unusual activity and we are working with our banking partners and law enforcement to investigate,” Drake said, reading from a prepared statement. “Protecting our customers’ information is something we take extremely seriously, and we are aggressively gathering facts at this point while working to protect customers. If we confirm that a breach has occurred, we will make sure customers are notified immediately. Right now, for security reasons, it would be inappropriate for us to speculate further – but we will provide further information as soon as possible.”

There are signs that the perpetrators of this apparent breach may be the same group of Russian and Ukrainian hackers responsible for the data breaches at Target, Sally Beauty and P.F. Chang’s, among others. The banks contacted by this reporter all purchased their customers’ cards from the same underground store — rescator[dot]cc — which on Sept. 2 moved two massive new batches of stolen cards onto the market.

In what can only be interpreted as intended retribution for U.S. and European sanctions against Russia for its aggressive actions in Ukraine, this crime shop has named its newest batch of cards “American Sanctions.” Stolen cards issued by European banks that were used in compromised US store locations are being sold under a new batch of cards labled “European Sanctions.”

It is not clear at this time how many stores may have been impacted, but preliminary analysis indicates the breach may extend across all 2,200 Home Depot stores in the United States. Home Depot also operates some 287 stores outside the U.S. including in Canada, Guam, Mexico, and Puerto Rico.

This is likely to be a fast-moving story with several updates as more information becomes available. Stay tuned.

Update: 1:50 p.m. ET: Several banks contacted by this reporter said they believe this breach may extend back to late April or early May 2014. If that is accurate — and if even a majority of Home Depot stores were compromised — this breach could be many times larger than Target, which had 40 million credit and debit cards stolen over a three-week period.

Tags: Home Depot breach, home depot data breach, home depot databreach, P.F. Chang's data breach, Paula Drake, rescator, Sally Beauty data breach, target data breach