New Delhi - Health authorities confirmed India's first case of swine flu Saturday, saying a 23-year-old man was quarantined in the southern city of Hyderabad after a trip to the United States.

A statement by the federal Health Ministry said the patient, who had flown Wednesday to Hyderabad, was shifted to an isolation facility with symptoms of the infection.

"His samples have tested positive for influenza A/H1N1," the Health Ministry said without naming the patient.

"The office of the concerned airline has been contacted to provide the list of passengers who travelled with him in close proximity," it said. "Information of such passengers would be provided to the WHO [World Health Organization] and respective countries through the External Affairs Ministry."

The passengers were advised to remain under home quarantine for seven days and monitor themselves for symptoms like fever, cough and difficulty in breathing.

They were also asked to provide contact details to authorities.

The WHO has said that 7,520 people have been infected with H1N1 in 34 countries. It has killed 65 people, it said.