Putin turned 70 on Friday, but the Kremlin reportedly discouraged local officials from throwing parties for fear of making the president look old.
In the video uploaded by St Petersburg TV, several hundred school pupils could be seen arranging themselves into a message saying “Putin is our president” on the city’s iconic Palace Square.
The video, which resembled the carefully choreographed propaganda more commonly seen on television screens in North Korea, was organised by the youth branch of the ruling United Russia party - but was taken offline after only a few hours.
One unnamed official said: “Why draw attention to the fact that our president has long been of the retirement age?”
Russia’s state-controlled newspapers on Friday ran pieces full of praise for the Russian leader of 22 years, crediting him for an economic miracle and the “enlargement of Russia” by annexing parts of Ukraine, but rarely mentioned his age.
Komsomolskaya Pravda, Russia’s best-selling tabloid, compared Putin to Catherine the Great for annexing parts of southern Ukraine and stopping the country from “falling apart”.
“Not a single state in the 21st century has gotten bigger,” it said.
North Korea’s Kim Jong Un was the first world leader to send a message to Putin to congratulate him on turning 70, hailing the president’s “distinguished leadership and strong will”.
Putin, who usually shuns public displays of adoration, on Friday hosted several leaders of former Soviet states for an informal summit in his hometown.
Alexander Lukashenko, the Belarusian dictator, gave Putin a gift certificate for a Belarus-made tractor for his birthday, according to his press office.
The president of Tajikistan offered a display of Central Asian melons and of watermelons which were piled on the grounds of the palace where the leaders were meeting.