Russia has agreed to lend Venezuela over $2bn (£1.2bn) to buy weapons, President Hugo Chavez has said.
The credit will be used to purchase nearly 100 tanks and a series of anti-aircraft rocket systems from Russia.
In his weekly TV address, Mr Chavez said the weapons were intended to boost Venezuela's defensive capacity.
The deal comes as tensions grow between Venezuela and Colombia over Bogota's plan to allow the US access to several military bases there.
Colombia says the US forces will help in the war against drugs and left-wing guerrillas, and will not destabilise the region.
"The Russian government approved financing of $2.2bn for the cost of the weapons," Mr Chavez said on his weekly programme "Alo Presidente".
The money would be used to buy arms including 92 T-72 tanks and an S-300 rocket launch system, he said.
Mr Chavez suggested that Colombia's decision to grant the US access to seven military bases was a threat to Venezuelan security.
He said the anti-aircraft rockets systems would make it difficult to be attacked.
"With these rockets, it is going to be very difficult for them [the US] to come and bomb us. If that happens, they should know that we will soon have these systems installed, [and] for an enemy that appears on the horizon, there it goes," he said.
Mr Chavez said that the country's vast reserves of oil and gas demanded military protection.
"Venezuela has no plans to invade anybody, nor attack anybody," he said. "These arms are necessary for our national defence."
He also reiterated that his government was committed to developing nuclear power with Russia's help.
"With Russia we have created an atomic energy commission and I tell the world - Venezuela is going to start developing nuclear energy, but we are not going to make an atomic bomb," Mr Chavez said.
The loan announcement came days after Mr Chavez returned from a 10-day tour of Africa, Asia and Europe, during which he held two days of talks in Moscow.
Over recent years the country has signed over $4bn worth of weapons contracts with Russia, including the purchase of 24 Sukhoi fighter jets, numerous combat helicopters and 100,000 Kalashnikov assault rifles.
Last November, the two states held joint exercises in the Caribbean Sea, close to US territorial waters.