The leaders also agreed to co-operate on nuclear and space programmes
Russian arms sales to Venezuela may reach $5bn (£3.3bn), Prime Minister Vladimir Putin has said, commenting on his visit last week to Caracas.
The deals include a $2.2bn seven-year loan that Moscow extended to Venezuelan President Hugo Chavez last year.
Mr Putin, speaking at a government meeting in Moscow, said the contracts would go to 13 Russian weapons firms.
Reacting to the news, the US said it failed to see what legitimate defence needs Venezuela had for the equipment.
"Our delegation just returned from Venezuela. I want to inform you that the total volume of orders could exceed $5bn," Mr Putin said at the Moscow meeting. He gave no further details of the deals.
President Chavez has already agreed military purchases worth more than $4bn with Moscow since 2005, including Sukhoi jet fighters, helicopters, tanks and assault rifles.
The Venezuelan leader dismissed US fears during Mr Putin's weekend visit.
"We are not building an alliance against the United States. We don't care what Washington thinks," Mr Chavez said on Friday.
Last November, Mr Chavez told his troops to "prepare for war" with neighbouring Colombia to counter a planned increase in the number of US troops based there.
Washington, which has previously expressed concern about Venezuela's arms purchases, said it did not understand why President Chavez's government needed more weapons.
"If Venezuela is going to increase its military hardware, we certainly don't want to see this hardware migrate to other parts of the hemisphere," state department spokesman PJ Crowley said.