Demonstration images of the tunnel, published by RIA, showed that masked people crossing it were sprayed with disinfectant on the ceiling and on the side.
The Russian news agency described the disinfectant as a thin cloud of liquid that covered people’s clothes and all exposed upper body flesh.
Putin spokesman Dmitry Peskov said in April that anyone who meets Putin in person has been tested for the new virus. A month later, Peskov declared that he himself had been infected.
Russia has registered more than 500,000 infections, the third highest number in the world after Brazil and the United States, which it attributes to a massive screening program.
Russia has so far recorded 7,284 deaths, less than many other countries. Critics doubt the accuracy of his mortality figures.