During the visit of Russian President Vladimir Putin to Minsk, a constitutional act will be signed that proclaims a union state of Russia and Belarus, Ekho Moskvy reports, citing sources close to Belarusian President Alexander Lukashenko. The document has already been prepared. According to sources, Vladimir Putin will become president of the Union State after leaving the post of president of Russia. Alexander Lukashenko will head the Union Parliament. Vladimir Putin's visit to Minsk will take place on December 13-14.