An apartment fire that claimed the lives of a Turkish mother and her 4-year-old son is believed to have been deliberately set, German authorities reported Wednesday.

"We do not believe there was a technical defect but rather that the fire was set intentionally," Ingo Kechichian, a spokesperson for public prosecutors, told public broadcaster RBB.

There were no immediate clues regarding the motive of the suspect(s).

The fire broke out early Sunday at a shop on the ground floor of a three-story building in Eberswalde, Brandenburg, in northeastern Germany.

The fire quickly spiraled out of control, injuring at least six people, with four of them seriously wounded, in addition to killing the mother and her son, according to fire department officials.

Police spokesperson Roland Kamenz told local media that authorities are investigating the blaze thoroughly without ruling out any potential causes.

The police department has appealed for witnesses and requested anyone with information to come forward and assist in the investigation.

In recent years, Germany has seen arson attacks targeting the homes of Turkish immigrant families.

In 1993, a Turkish immigrant home in the German town of Solingen was set ablaze by four young far-right extremists, killing five members of the Genc family – two women and three girls – while 14 others were wounded, including several children.