NEW YORK (AP) -- The discovery of two more dead birds infected with the West Nile virus prompted New York City on Sunday to expand its battle against disease-carrying mosquitoes.

Mayor Rudolph Giuliani said the city still has had no reports of humans afflicted with the sometimes-deadly ailment. Seven people died and more than 60 were made ill by an outbreak of the virus a year ago.

Giuliani said spraying efforts will be expanded into areas of Queens and Brooklyn in attempt to kill mosquitoes that might be carrying the virus. The city is going ahead with further efforts in Staten Island.

''People should not be alarmed, should not be concerned. These are all things that we assumed we would have to do,'' Giuliani said.

New York health officials have now found seven birds infected with West Nile.