The aid group said Friday that the exact circumstances of the gunfire a day earlier is not immediately clear. However, a security guard, Ahmed Ali, said Thursday that a disgruntled former employee of Doctors Without Borders, a Somali dismissed the day before, had returned and opened fire.

The aid group identified the victims as Philippe Havet, 53, of Belgium, and Andrias Karel Keiluhu, 44, an Indonesian doctor best known as Kace.

In its statement, Doctors Without Borders said one victim died on the spot and the second at a hospital after surgery.