In terms of total dollar market value, Russian oil company Rosneft said it's well ahead of its other counterparts in the nation's energy sector.

Rosneft President Igor Sechin, a close ally of Russian President Vladimir Putin, said his company was now bigger than Gazprom, among the energy companies in the world.

"We're well ahead of other Russian companies in terms of market capitalization, while the gap in valuation with the second-biggest company (in the country) Gazprom has exceeded $5 billion," he was quoted by Russian news agency ITAR-Tass as saying.

Rosneft last week reported total revenue for the first quarter of 2016 at $14.5 billion, about 22 percent lower than the previous quarter. Most companies are reporting weak figures for the first quarter as the price of crude oil dipped below $30 per barrel during that period, its lowest point for the year.

Free cash flow of $1.5 billion was about 40 percent lower than first quarter 2015 and the company's net debt increased by 4 percent.

Last week, Gazprom Chairman Alexei Miller met with Vagit Alekperov, the president of Russian oil company Lukoil to discuss the terms of a strategic partnership agreement extending through 2025. Gazprom said both sides discussed the potential for long-term purchases of gas associated with some of the fields in its counterpart's portfolio.

Under pressure from European leaders wary of Russia's grip on the energy sector, Gazprom has said export diversification was a top priority during the market downturn. In terms of revenue, Rosneft said it managed to exploit the appropriate trading channels in a way that offset some of the pressures from lower crude oil prices while at the same time meeting its domestic and global contractual agreements.

The World Bank estimates the Russian economy will linger in recession in part because of weak conditions in the oil market.