North Korea says it has developed a vaccine against the highly virulent strain of bird flu and is inoculating chickens to prevent the disease following outbreaks in South Korea.

The director of the North's Veterinary and Anti-Epidemic Department told AP Television News Thursday that the North has recently increased production of a locally developed H-5-N-1 vaccine.

The official did not mention when the vaccine was developed or how effective it is.

Bird flu hit North Korea early last year, resulting in the slaughter of about 210-thousand chickens and other poultry. No new cases have been reported since.