BUENOS AIRES, Argentina — Argentine health authorities on Tuesday confirmed three more H1N1 flu deaths, bringing the nation's total to four as it enters the South American winter flu season.

Two of the patients who died lived in Buenos Aires province and one in the Argentine capital itself, Vice Minister of Health Carlos Soratti told a news conference.

Claudio Zin, health minister for Buenos Aires province, told Todo Noticias television that one of the three fatalies was a 28-year-old man who had received a bone marrow transplant for leukemia 10 years ago. No information was released on the other two victims.

Argentina's first H1N1 flu fatality was a 3-year-old infant whose death was confirmed Monday.

Soratti said tests had confirmed 138 new cases of H1N1 flu, bringing Argentina's total to 871, the second highest in South America after Chile which has at least 2,335 cases.

While the H1N1 flu has hit Mexico and the United States the hardest, South America has now suffered seven deaths with four in Argentina, two in Chile and one in Colombia.

Experts have expressed concern that while Mexico has likely seen the worst of the H1N1 flu, the virus will likely continue to spread worldwide as flu season ramps up in the Southern Hemisphere.

The World Health Organization declared the H1N1 flu a pandemic last week. As of Monday, the WHO said 76 countries have reported nearly 36,000 cases of the virus, with 163 deaths worldwide. That figure did not include the latest deaths in Argentina.