Ho Chi Minh City has ordered the slaughter of all poultry in hopes of stamping out the deadly bird flu virus that has killed 13 people in Vietnam in recent weeks, state media said on Wednesday.

The city of 10 million people, which is near the Mekong Delta where Vietnam’s latest outbreak of the H5N1 virus began, had already ordered the killing of all its ducks, which can carry the disease without showing symptoms.

But state newspapers said the government of Vietnam’s largest city had ordered the slaughter extended to all poultry and the killing would begin on Friday.

It is the latest tough action taken in the communist country’s war against a virus that experts fear could mutate into a form that could pass between humans and cause a pandemic that might kill millions in a world without immunity.

The government curbed the movement of poultry in the run up to last week’s Tet, the Lunar New Year festival, banned the raising of all waterfowl until June 30 and called for international expertise to help roll the virus back.

Officials say it is working with the outbreak of the virus, which kills 80 percent of its human victims, showing signs of subsiding and no reports of new human victims in the past week.

On Wednesday, the animal health department said in a report the H5N1 virus, which has killed 45 people since it arrived in Asia in late 2003, had surfaced in three provinces this week.

But the virus, which has spread to more than half Vietnam’s 64 provinces and cities since it re-emerged in December, had caused no new infections in poultry in seven of the affected provinces over the last three weeks, it said.

Next week, the U.N. food agency and the World Organization for Animal Health will hold a regional meeting in Ho Chi Minh City to discuss the emergency.