The first case of bird flu has been detected in Iran, officials there say, but it is unclear whether it is the deadly H5N1 strain.
Tests in Iran and abroad confirmed 135 swans had died of the virus in Anzali marshes, near Bandar Anzali in the north-west, in the past two weeks.
But statements conflict on the nature of the virus.
The finding follows reports of bird flu in wild water fowl further up the Caspian Sea coast in Azerbaijan.
A statement from the Iranian State Veterinary Organisation said only that the tests had shown the presence of the H5 virus, which kills only birds.
The highly-pathogenic H5N1 sub-strain has killed five people in Iraq and Turkey in recent months.
However, an official from the veterinary organisation, who declined to be named, told the Reuters news agency the strain was H5N1.
The official state news agency, Irna, also reported that "laboratory tests have confirmed H5N1 flu was the cause of death" of the 135 swans.