Moscow/Orenburg, Russia - The Venezuelan and Russian presidents met in southern Russia Friday as the countries agreed to expand energy and military ties in an effort to close ranks in opposition to the United States.

Hugo Chavez and Dmitry Medvedev presided over the signing of deals between their energy ministries and state energy companies Petroleos de Venezuela, or PSVSA, and Gazprom for greater cooperation in the oil and gas sector.

Later the presidents were to watch large-scale military exercise in city of Orenburg, near Russia's border with Kazakhstan.

The Venezuelan leader's visit comes as four Russian warships sailed to Venezuela for joint military exercises in the Caribbean, while two Russian Tu-160 nuclear bombers flew sorties over the US- patrolled waters from a base in Venezuela last week.

This is Chavez's second trip to Russia in as many months, and he was greeted by Prime Minister Vladimir Putin late Thursday with an offers to hike arms sales to Venezuela and share nuclear energy expertise.

Russia's rapprochement with fiery US critic Chavez looks set to exacerbate an already tense security standoff with Washington over Russia's war with US ally Georgia last month.

"Latin America is becoming a noticeable link in the chain of the multi-polar world that is forming," Putin said ahead of talks with Chavez at his country residence. "We will pay more and more mind to this vector of our economic and foreign policy."

A Kremlin official, who spoke on the usual condition of anonymity, said Thursday that Russia would loan 1 billion dollars to Caracas for future weapons purchases.

Russia has sealed weapons contracts with Venezuela worth more than 4.4 billion dollars from 2005, the official said.

Russian newspapers reported that Venezuela sought more Sukhoi fighter jets, Kalashnikov assault rifles and missile defence systems to modernize its military.

Russian energy giant Gazprom said it had invested 100 million in Venezuela, CEO Alexei Miller was quoted by news agency Interfax as saying, adding agreements to form consortium with PSVSA was in the works.

Putin also said that Russia was "ready to look at the possibility of cooperation in the sphere of nuclear energy." He did not give further details.

Moscow has butted heads with Washington in its effort to market its nuclear power expertise since the fall of the Soviet Union.

Disagreements this week forced the cancellation of UN talks on more sanctions on Iran for its nuclear energy programme, developed in cooperation with Russia.

Both leaders have said their partnership aims to decrease US influence.

In an interview with Russia's Vesti-24 television station Chavez said on Sunday that "Latin America needs friends like Russia now" to rid itself of "imperial domination."

Popular Russian daily Moskovsky Kommsomolets summed up the growing relations between both states as "the enemy of my enemy is my friend," and state mouthpiece Rossiiskaya Gazeta wrote Friday that anti-Americanism was the "catalyst" for warming relations.