A health official said hospitals in the area had received 229 corpses from the stricken village of Dronka and a security source said another 122 corpses were still on the ground in Dronka.
Flash floods killed 63 other people in Assiut and neighbouring provinces, security sources said.
Lightning struck the complex of eight fuel tanks Wednesday morning after a thunderstorm had raged across much of Egypt for up to five hours.
Officials said three of the storage tanks, each holding about 5,000 tons of fuel for the army, exploded and spilt burning fuel into the village, which lies about 320 kilometers south of Cairo.
More than 200 houses in Dronka were destroyed and at least 20,000 people left and headed for the provincial capital Assiut, eight kilometers east.
"It was like napalm," said one man whose three brothers died in the fire.
One of the fuel tanks is still ablaze and the other five could catch fire if the wind changes, officials said.
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