"Representatives of the gay movement are threatening to hold their action on May 16 regardless of whether they have permission for it or not, without any consideration for the opinions of the public majority," Sergei Tsoi said.
"The Moscow government is declaring that there has never been and never will be a gay parade in Moscow!" he announced.
Tsoi said such events are aimed at "not only destroying the moral foundations of our society but deliberately provoking disorder threatening the lives and security of Muscovites and guests to the capital."
"First of all, such an action threatens the security of those willing to take part in it. All this is absolutely unacceptable," Tsoi said.
"This is not only the position of the Moscow government. Representatives of all religious groups, and above all the Russian Orthodox Church, as well as leaders from youth and veteran organizations and multi-cultural societies have issued a strong warning against it," the spokesman said.
Tsoi said any attempts to hold an unauthorized parade would be stopped by the authorities in line with the law.
The head of the Gay Russia Project, Nikolai Alekseyev, said earlier that several public gay events have been scheduled for May 16, when the final of the 2009 Eurovision Song Contest is due to take place in Moscow.
Over the past three years, the Moscow city authorities have rejected official applications by organizers seeking permission to hold gay parades, on the grounds that the event would interfere with the rights and everyday lives of ordinary Muscovites.
An unsanctioned gay parade took place on Moscow's main Tverskaya Street on June 1, 2008, gathering around 200 people, mostly journalists and curious passers-by. Thirteen people were detained by Moscow police.
Russian gay rights activists have appealed to the European Court of Human Rights five times against decisions by the Russian authorities to ban gay marches in May 2006 and May 2007, and three pickets in 2007.
Moscow Mayor Yury Luzhkov has branded gay parades "Satanic" and vowed that they will never be permitted in the capital, while the Russian Orthodox Church and various far-right groups have vowed to halt any attempt to hold a march in support of gay rights in Russia.