CARACAS, Venezuela — Venezuela and Russia are strengthening their strategic alliance with new plans to cooperate on oil production, weapons and even wireless technology, the governments said as two visiting Russian Tu-160 bombers left for home on Thursday.

Venezuelan President Hugo Chavez, traveling to Moscow next week at the invitation of Prime Minister Vladimir Putin, is planning new oil projects with Russian companies and joint military exercises with Russian warplanes and ships in the Caribbean in November.

Venezuela also is in talks to buy Russian air defense systems and armored vehicles, and has expressed interest in the new Su-35 fighter, due off assembly lines in 2010, said Sergei Chemezov, general director of the Russian state holding company Rostekhnologii, according to Russia's Interfax news agency.

The allies have sealed more than $4 billion in defense contracts since 2005. Venezuela has bought Sukhoi fighter planes, Mi-17 helicopters, and 100,000 Kalashnikov assault rifles, most of which have already been delivered.

Chemezov spoke to reporters in Caracas while accompanying Russia's Deputy Prime Minister Igor Sechin. He stressed that while energy cooperation is paramount, the military relationship also is strengthening.

Russia also plans to help Venezuela build factories to make ships, cars, rifles and ammunition, and a center to train pilots and fix helicopters is in the works. Russian officials even offered to install broadband wireless networks to provide cheap Internet and telephone service to Caracas, Chemezov told Russia's Itar-Tass news agency.

The countries' military cooperation is growing "more solid every day," Venezuelaan Defense Minister Gen. Gustavo Rangel said.

Their alliance was mocked on Thursday by U.S. Secretary of State Condoleezza Rice, who said Russia is only isolating itself.

The United States is confident that its own relations with Western Hemisphere countries "will in no way be diminished by a few, aging Blackjack bombers visiting one of Latin America's few autocracies," she said.

Chavez, who expelled the U.S. ambassador to Caracas last week while accusing Washington of backing a plot against him, told reporters this week that the alliance doesn't pose a threat to any other country, and that he welcomes Russian help in research, economic development and defense technology.

Russia's economic influence is clearly expanding in the Americas. Bolivia announced Thursday that it would sign an oil and natural gas exploration deal with Gazprom. Terms of the deal weren't immediately disclosed.

And Sechin announced that five of Russia's biggest oil companies are looking to form a consortium to increase Latin American operations. State-controlled Rosneft, Lukoil, Gazprom Neft, Surgutneftegaz and TNK-BP hope to build a $6.5 billion refinery to process Venezuela's tar-like heavy crude, Russia's RIA Novosti news agency reported.

Such an investment could help Venezuela, the world's ninth biggest oil producer, wean itself off the U.S. refineries it now depends on to process much of its crude. Already, Chavez has moved to push out private companies including Exxon Mobil, Chevron and ConocoPhillips while striking new oil development agreements with state oil companies from Iran and China.

Russian companies Gazprom and Lukoil also signed agreements with Venezuelan state oil company Petroleos de Venezuela SA to jointly explore several Orinoco fields.