Ukrainian President Volodymyr Zelenskyy said his country did not inform their allies about the planned incursion on Kursk because it would have seemed "unrealistic" to them.Genya Savilov/AFP via Getty ImagesUkraine didn't inform its allies about its planned incursion on Russia's Kursk region.The country's leader, Volodymyr Zelenskyy, said allies would have called the invasion "unrealistic."Ukraine ended up notching significant battlefield gains after catching the Russians off guard.Ukrainian President Volodymyr Zelenskyy says his country kept its allies in the dark about its plans to attack Russia's Kursk region because they "would have said that it was unrealistic.""This is why nobody had been informed about our preparations," Zelenskyy told the heads of Ukraine's foreign diplomatic missions in a speech delivered on Monday, according to a translation by Ukrainian media outlet Pravda."Now the real success speaks for itself: our active defensive actions on the other side of the border and Putin's inability to protect his territory from our defensive actions of this kind are very telling," he continued, referencing Russian leader Vladimir Putin.Ukraine's allies weren't the only ones who didn't know about the attack.