SEOUL - SOUTH Korea said on Friday it was investigating three new reports of suspected bird flu and sent more soldiers to cull poultry as the worst outbreak in four years spread.
The Farm Ministry said there were two more suspected cases at poultry farms in North and South Jeolla provinces, some 320km south of Seoul, where the first bird flu recurrence for a year was reported this month.

It also said a suspected case had been reported at a duck farm in Gongju in South Chungcheong province, 130km south of Seoul, suggesting the virus is spreading at its fastest rate since the country reported its first case in 2003.

South Korea has confirmed 15 cases of the deadly H5N1 strain in just two weeks.

'We are stepping up quarantine work even in unaffected areas and will slaughter hundreds of thousands of birds in the confirmed sites,' the ministry said in a statement.

It has culled 3.3 million chickens and ducks, the largest since the country killed 5.3 million between late 2003 and early 2004, and said it would send 450 soldiers to help quarantine work on Friday.

Authorities have come under heavy criticism for failing to provide explanations for the fast spread of the virus.

South Korea had seven bird flu outbreaks between November 2006 and March last year. No human deaths have been reported.

Some 240 human deaths have been reported globally from the H5N1 strain and 381 confirmed cases of infection since 2003, according to World Health Organisation data.