Brazil will mobilise some 220,000 troops in the battle against the mosquito blamed for spreading a virus linked to birth defects, the country's health minister said.
Marcelo Castro said that nearly 220,000 members of Brazil's armed forces will go door-to-door to help in mosquito eradication efforts, according to Rio de Janeiro's O Globo newspaper.
It also quoted Mr Castro as saying the government would distribute mosquito repellent to some 400,000 pregnant women who receive cash-transfer benefits.
And all major Brazilian dailies quoted Mr Castro as saying the country is "badly losing the battle" against the Aedes aegypti mosquito that transmits Zika, dengue, chikungunya and yellow fever.
"The mosquito has been here in Brazil for three decades, and we are badly losing the battle against the mosquito," the Folha de S Paulo newspaper quoted him as saying as a crisis group on Zika was meeting in the capital, Brasilia.
Worry about the rapid spread of Zika has expanded across the nation, and the hemisphere beyond.
Repellent has disappeared from many Brazilian pharmacies and prices for the product have tripled or even quadrupled where it is still available in recent weeks since the government announced a suspected link between Zika virus and microcephaly, a rare birth defect that sees babies born with unusually small heads and can cause lasting developmental problems.
Nearly 4,000 suspected cases of microcephaly have been reported since October, compared with fewer than 150 cases in the country in all of 2014.
The US Centres for Disease Control and Prevention has advised pregnant women to reconsider travel to Brazil and 21 other countries and territories with Zika outbreaks over fears about microcephaly.
Both Brazil's Zika outbreak and the spike in microcephaly have been concentrated in the poor and underdeveloped north east of the country, though the prosperous south east, where Sao Paulo and Rio de Janeiro are located, is the second hardest-hit region.
Officials in Rio also ramped up their fight against the Aedes aegypti, dispatching a team of fumigators to the Sambadrome, where the city's Carnival parades will take place next month. Governor Luiz Fernando Pezao was to be on hand for a ceremonial handover of around 30 vehicles to help poor Rio suburbs fight the spread of the mosquito, his team said.
Officials have also pledged to redouble mosquito eradication efforts during the Olympics. Rio will host the August 5-21 Games.
Argentina authorities say they are investigating a possible case of infection by the mosquito-borne Zika virus. It would be a first for the nation that shares a border with Brazil.
Santa Fe health department official Andrea Uboldi told La Red radio that the man is in the city of Rosario and had recently visited Brazil, where hundreds of thousands of cases of Zika are suspected and authorities are investigating a possible link to birth defects.
Meanwhile, officials in the Argentine province of Corrientes have declared an epidemiological alert due to an outbreak of dengue in the area. Dengue and Zika are both transmitted by the Aedes aegypti mosquito.