I'm not the expert on baltic gods, but from the research that ReDeR made, which is great( but google sucks in translating Lithuanian into English

), Perkunas sometimes is symbolized with the flaming sword and it is believed that when he swings his sword he releases bolts of lighting, so here is the similarity. But for fire balts, or Lithuanians if to be more precise, also have two other gods:
Dimstipatis - "lietuvių namų, sodybos, taip pat ugnies dievas. Jam aukojama norint apsaugoti namus nuo ugnies." God of people's homes and fire, sacrifices are brought to him to protect home from fire.
Gabija - "ugnies Deivė, dar įvardijima kaip Pelengabija, Matergabija ir pan., namų židinio globėja. Sūkurėlis arba Svastika - kryžma su užlenktais galais, tai išplėtotas ugnies ženklas". Goddess of fire also called Pelengabija, Matergabija. She watches over a home's fireside.
There is also few other gods that are connected to fire like blacksmiths furnace's god, holy fire's goddess and some others.
Please correct me if there is any mistakes in these reasoning
