President Vladimir Putin told pupils at the start of the school year on Friday that it was impossible to defeat Russia as Moscow's offensive in Ukraine grinds through its 19th month."I understood why we won the Great Patriotic War," Putin said, referring to World War II, adding: "It is impossible to defeat this kind of nation with this kind of attitude.

We were absolutely invincible.

And we are the same now."Putin spoke to the children during a lecture called "Important Conversations." Thirty high-achieving schoolchildren were selected to attend Putin's lecture."Important Conversations" were introduced after the start of the Kremlin's assault on Ukraine to boost patriotic sentiment.The patriotism classes combine World War II revisionism, lessons on Russian values and the Kremlin's narrative about Moscow's troops "protecting" compatriots in Ukraine.Across Russia, schoolchildren have been encouraged to send letters to Russian soldiers in Ukraine and make camouflage nets and candles for the trenches.During the lecture, Putin said that Russia would seek to "ensure security" in the four Ukrainian regions the Kremlin claimed to have annexed last year without fully controlling them.Last year Putin traveled to the Russian exclave of Kaliningrad for the start of the school year, saying Moscow sent troops to Ukraine to "protect Russia."In June, Kyiv launched its long-anticipated counteroffensive but has acknowledged tough battles as it struggles to break through heavily fortified Russian positions.