Authorities have detected the deadly H5N1 strain of bird flu in dead crows in Pakistan´s capital, officials said Thursday.

About 40 dead crows had been found in the past two weeks in and around Islamabad, Agriculture and Livestock Ministry spokesman Mohammad Afzal told AFP. Eight of them were tested and two birds were found to be carrying H5N1.

"We are fully alert and monitoring the situation," Afzal said, adding there was no sign of the virus as yet in any poultry farms in the country.

Last month Islamabad´s zoo was shut down and dozens of birds were slaughtered after the bird flu virus was found in peacocks and geese.

Pakistan´s first H5N1 cases were detected in March 2006 at two chicken farms in North West Frontier Province, prompting consumer panic and a mass slaughter at several sites.

The virus resurfaced in early February among chickens in Rawalpindi, adjoining Islamabad, and in peacocks in the northwestern city of Mansehra.