Russia’s OAO Rosneft and OAO Gazprom signed a cooperation accord with Venezuela’s state oil company Petroleos de Venezuela SA late yesterday at a ceremony in Caracas led by President Hugo Chavez and Russian Deputy Prime Minister Igor Sechin.

“We’re working on large-dimension projects from oil, gas and petrochemicals to finance, banking and trade,” Chavez said on state television.

Chavez, who has led the OPEC-member nation since 1999, has strengthened ties with Russia during his 12-year rule in a bid to re-equip his military after a U.S. arms embargo and to attract investment in the energy industry.

The $4 billion defense loan will be disbursed in two equal parts in 2012 and 2013, Chavez said today. A bi-national bank, known as Evrofinance Mosnarbank SA, will boost its capital to $4 billion and provide lending for housing projects and a joint- venture oil project in the Junin 6 block, he said.

Rosneft will develop the Carabobo 2 heavy-crude block in the Orinoco as a minority partner along with PDVSA. Carabobo 2 was the last block to be assigned under a 2010 bid round.

Venezuela assigned the other two blocks to groups led by Chevron Corp. and Repsol YPF SA last year.

State-controlled gas producer Gazprom will explore for natural gas in the Gulf of Venezuela, close to the Perla field where Eni SpA and Repsol have 15 trillion cubic feet of certified gas reserves.

Gazprom and PDVSA agreed to consider a joint venture for the development of the Robalo gas deposit, the Moscow-based gas exporter said today in an e-mailed statement. The companies will hold talks to define stakes, it said.