Russia and Argentina have signed a series of framework agreements on economic and energy co-operation following talks in Moscow.
Argentine President Cristina Fernandez de Kirchner and Russian leader Vladimir Putin hailed their co-operation as a "comprehensive strategic partnership".
The agreements include Russian investment in a hydroelectric plant and a nuclear power plant in Argentina.
There was also a memorandum of co-operation on defence.
Correspondents say the Kremlin is keen to boost trade relations with Latin America to offset the effects of sanctions imposed by Europe and the US over the Ukrainian crisis.
Argentina is looking for foreign investment as its battles US hedge funds thwarting its effort to restructure defaulted debt.
Among the framework agreements was a Russian pledge to finance a hydroelectric power plant on Argentina's Neuquen River.
Russia's Rosatom nuclear corporation also agreed to build a new reactor at Argentina's Atucha 3 nuclear power plant.
Rosatom chief Sergei Kiriyenko said he hoped the final deal would be signed by the end of the year.
Mr Putin said the project would bring "the latest Russian technology" to Argentina.
He also said the two countries had agreed to expand co-operation between their defence agencies.
He added that Russia "supports Argentina" in its attempts to have direct talks with the UK over the disputed Falkland Islands, known in Argentina as the Malvinas.