Argentina has reported four more swine flu deaths, raising to 21 the number of people who have died with the A(H1N1) virus since it was first confirmed in the South American country in early May.
The health ministry said in a daily update on Wednesday that the number of confirmed swine flu cases rose by nearly 100, to 1,391, while another 967 people suspected of contracting the virus were being tested.
"The most affected zone is the metropolitan area" of Buenos Aires, Health Minister Graciela Ocana said.
According to the ministry, 20 of the fatalities and 1,191 of the positive cases have occurred in or around Buenos Aires, an area with a total of 12.5 million people.
With the southern hemisphere now in winter, the A(H1N1) virus has spread more broadly in Argentina and neighbouring Chile than in most parts of Latin America, making it a closely watched harbinger of the flu season to come in the northern hemisphere.
As Argentina has reported 11 fatalities in the past two days, health officials were raising concerns about the epidemic as the country prepares for Sunday's legislative elections.
In Peru, the number of new confirmed cases rose by 55, to 299 total, health officials there said.