"A resident of the Podolsk District [south of Moscow] bought a chicken on Moscow's Ptichy pet market, and forty-four birds at his farmstead died as a result," Alexei Panteleyev said.
Russia's chief epidemiologist, Gennady Onishchenko, on Friday confirmed bird flu as the cause of poultry deaths in two other households outside the capital - in the southern Domodedovo District and in Odintsovo, to the west.
The animal and plant health watchdog, Rosselkhoznadzor, said earlier Saturday the dead birds there have been traced to the same Moscow market and that they were presumably brought in from other regions.
Russia recorded its first cases of bird flu in August 2005, but until now, outbreaks have occurred only in southern provinces and in Siberia.
All pavilions that sell birds at Moscow's Ptichy market have been closed since Friday, and veterinary inspectors are now looking for any traces of the virus there.
A telephone hotline has been opened for residents of the Moscow Region who bought any birds on the Ptichy market after February 1.
It is yet unclear whether H5N1, a strain potentially lethal to humans, is responsible for the poultry deaths near Moscow, but strict security measures are now being taken all across the region to prevent the virus spreading to commercial farms.