Both leaders said the nuclear projects would be for peaceful purposes.
Russia also hopes to build bases in Argentina for its satellite system and cooperate over the use of military technology, Mr. Putin said, including the use of Russian planes and helicopters in the sector of Antarctica claimed by Argentina. Russian companies may also take part in the construction of two hydroelectric plants here.
On Friday, Mr. Putin brokered deals between Russian and Cuban energy companies in Havana, and waived 90 percent of Cuba's Soviet-era debt.
He is also expected to sign a nuclear agreement with Brazil, a Russian official said, and he will hold talks with President Dilma Rousseff of Brazil before a meeting next week of the emerging market nations known as the Brics group: Brazil, Russia, India, China and South Africa.
Mr. Putin and Mrs. Kirchner did not announce an agreement for Russian investment in Vaca Muerta, a vast shale oil and gas field in Patagonia, but Mrs. Kirchner said that a Russian delegation would visit the field...