Fig & Olive restaurant in City Center closed Thursday night amid concerns about an outbreak that hospitalized four people with salmonella-like symptoms.

The D.C. Department of Health is trying to determine the source of the outbreak. Environmental and food samples have been collected.

Twenty cases of possible salmonella have been identified, but only two have been confirmed.

Three of those cases occurred over Labor Day weekend, as people were admitted to Sibley Memorial Hospital.

A spokeswoman for Fig & Olive says the restaurant is cooperating with the health department.

Fig and Olive released the following statement:

“The health and safety of our restaurants and patrons is of paramount importance to us. Fig & Olive has closed the City Center DC restaurant due to reports that some patrons have recently been sickened. We have retained third-party consultants to provide assistance in this investigation and will cooperate fully with the Department of Health. We will continue to work with the DOH to insure that we have done all we can for the safety of our customers.”