SEOUL, Sept. 11 (UPI) -- South Korean officials told provincial and municipal governments Friday to avoid public gatherings that could become H1N1 flu breeding grounds.

The warning came amid mounting concern over type-A H1N1 virus that has claimed five lives since the flu was first reported in South Korea in May, the Yonhap News Agency said.

South Korea has confirmed more than 7,000 infections of the H1N1 virus, formerly called swine flu.

"We recommend that regional governments call off or delay indoor events where highly vulnerable people are expected to attend," the government said in an e-mail message.

It listed the "highly vulnerable" as children below age 5 and seniors 65 or older, pregnant women and people with chronic diseases or weak immune systems.

The Ministry for Health, Welfare and Family Affairs said the advisory went into effect on Friday and would continue until the pandemic risk subsides.