Hudson's Bay, a Canada-based department store operator whose brands include Saks Fifth Avenue and Lord & Taylor's, announced Sunday night that that hackers compromised some 5 million credit and debit cards.

"Once we have more clarity around the facts, we will notify our customers quickly and will offer those impacted free identity protection services, including credit and web monitoring," Hudson's Bay said in a statement.

Cybersecurity firm Gemini Advisory reported the security breach.

Hudson's Bay is advising customers to review account data and alert the company to any unauthorized transactions, according to a New York Post report, which noted it is the second security breach the company has dealt with in the past 12 months.