These small white mushrooms started growing in a small pot. The location is Israel, on a higher floor in the building.
Is this Amanita smithiana ?
The flattened tops and long stalks make it more likely they're young versions of the Onion Stalked Lepiota, now officially known as Leucocoprinus cepaestipes, although the stalks look a little thick - they may thin out as the mushrooms develop. http://www.mykoweb.com/CAF/species/Leucocoprinus_cepaestipes.html
If its one of the amanitas, Amanita phalloides is more likely, but they have a smooth surface to the caps even when they're young.
Where the pot is inside a building is irrelevant - these will have come from mycelium present in the soil, and are just the fruiting bodies off that. You can snap them off and dispose of them if you like, but probably safest to wear gloves - they may well recur over time though.