NEW YORK — Home Depot confirmed on Monday that its payment systems have been hacked in a data breach that could affect millions of shoppers who used credit and debit cards at its U.S. and Canadian stores.

The breach could turn out to be one of the biggest in history. Home Depot did not say how many cards might be affected, but the largest U.S. home improvement chain did say its investigation into the breach goes as far back as April.

The news comes nearly a week after a website that focuses on cybersecurity reported on Tuesday a possible hack of Home Depot’s data. The company said later that day that it was investigating.

Home Depot is the latest retailer to have a data breach. Others include Target, luxury retailer Neiman Marcus, grocer Supervalu, restaurant chain P.F. Chang’s and the thrift store operations of Goodwill.

In December, Target disclosed a massive data breach that was the second-largest in history, resulting in the theft of 40 million debit and credit card numbers and the potential exposure of personal information of up to 70 million shoppers.

Forrester Research analyst John Kindervag said the Home Depot breach could affect similar numbers of shoppers or cards.

The retail breaches have rattled shoppers’ confidence at a time when privacy concerns are high. It’s also increased pressure on retailers to increase security so that customers can feel safe.