JAKARTA, Indonesia — Indonesia will ban the trade of live chickens in the capital of Jakarta beginning in 2010 to fight bird flu in world's hardest-hit nation, a livestock official said today.

Poultry will have to be killed at government-licensed slaughterhouses outside Jakarta before being transported to market, said Edy Setiarto, adding that authorities need two years to prepare regulations and business owners for the change.

Currently, many customers prefer to buy live chickens, which are then slaughtered to ensure the meat is fresh.

Setiarto said 70 percent of Indonesia's bird flu cases occur in Jakarta and surrounding districts. Last year, city residents were told they could no longer keep backyard chickens, but the order appears to have been largely ignored.

"The government will improve efforts to stop the spread of bird flu," Setiarto said.

Bird flu started sweeping through poultry populations across Asia in 2003 and has since jumped to humans, killing at least 236 people, nearly half of them in Indonesia, with 105. It remains hard for people to catch, but experts worry the virus could mutate into a form that passes easily among humans, sparking a pandemic. So far, most human cases have been linked to contact with infected birds.

Despite millions of dollars in international aid, the U.N. Food and Agriculture Organization said this month the virus was entrenched in 31 of Indonesia's 33 provinces. It warned of an increased possibility that the virus may mutate into a deadlier form.