Fast-food chain McDonald's Corp is working with police investigators to gain access to hackers who breached its database containing personal information of customers.

On Monday, McDonald's Corp reported that hackers used a third-party hired by it to gain access to a database containing personal information such as the birth dates and email addresses of its customers.

However, the company assured that hackers could not access sensitive financial information such as social Security numbers and credit card accounts.

McDonald's spokeswoman Danya Proud said that the hacked data was on computer systems operated by their long-time partner Arc Worldwide.

Commenting on the issue, Proud said, "The incident has resulted in an investigation by law enforcement authorities. Arc and McDonald's are cooperating with the appropriate authorities.”

She added that they were also working with Arc Worldwide to determine how the security was bypassed.

McDonald's Corp is alerting customers that their personal information may have been hacked. It is urging them to remain more vigilant about potential identity or phishing thefts.