Company officials from a Russian oil consortium were to visit Venezuela's eastern oil-producing region Monday, an area where it plans to explore for extra-heavy crude.

Company officials from a Russian oil consortium were to visit Venezuela's eastern oil-producing region Monday, an area where it plans to explore for extra-heavy crude.

Directors from Lukoil (LUKOY), Gazprom (SIBN.RS), Rosneft (ROSN.RS) and other Russian firms, accompanied by Venezuela's oil minister, planned to inspect an oil block that used to be controlled by the U.S. firm Conoco but after a nationalization is now 100% owned and operated by Venezuela state firm Petroleos de Venezuela, PdVSA.

The Russians planned to gauge environmental matters and look at other technical aspects of the area, PdVSA said.

The Russian consortium is set to finalize a deal to explore the Junin 6 block, but has not begun any drilling. It would be a joint venture with PdVSA which would be the controlling entity.

The Junin 6 block is separate from an ongoing bidding round for four other blocks in the eastern Orinoco region that PdVSA has opened to foreign firms. The deadline for companies to bid on the blocks was set for Tuesday, but it wasn't clear if that deadline may be pushed back. Chevron (CVX), some Russian companies and more than a dozen other firms have expressed interest in the bidding round, known as the Carabobo project. It is the first bidding open to foreign investors in years.

The Russian firms' activity in Venezuela's oil region Monday comes after the heads of Russia and Venezuela met last year and agreed to increase relationships to produce and sell oil and gas. At the same time, they also have forged tighter military relationships, which has been of concern to some in Washington.

PdVSA also invited foreign journalists to the area Monday, and the oil minister, Rafael Ramirez was expected to speak later.