Argentina has been building nuclear-powered electricity plants to revive its nuclear programme and reduce its dependence on fossil fuels amid an energy crunch.
Putin and President Cristina Fernandez said the Russian atomic energy corporation, Rosatom, would be involved with the construction of units in Argentina's Atucha III nuclear power plant.
"These are very important agreements," said Fernandez, who had been out of the public eye for a week due to a throat infection.
"They reaffirm our bonds of friendship and strategic links."
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Argentina has one of the world's largest deposits of shale oil and gas, but only a few companies have made commitments to develop the fields as many fear the government's interventionist energy policies.
Although a deal on the shale deposits was not announced yesterday, Fernandez said members of the Russian delegation travelling with Putin will visit Argentina's Vaca Muerta (Dead Cow) deposit in Neuquen province.
"We're talking about Russia, one of the world's top producers of gas and oil in the world. But we Argentines also have our own and it seems like others have noticed," Fernandez said.
"Argentina is one of Russia's top strategic partners in Latin America. We cooperate in vast sectors and I'm in constant contact with the president," Putin said. "We also have similar positions in the international arena."
About 150 members of the local Ukranian community waved flags and held large banners outside the Pink House presidential palace to protest Russia's annexation of Crimea and alleged support for separatists elsewhere in Ukraine.
German Chancellor Angela Merkel and French President Francois Hollande urged Russia this week to use its influence on rebels in eastern Ukraine so a meeting on a possible cease-fire can take place as soon as possible.