President Vladimir Putin of Russia signed a decree on Tuesday to protect Gazprom against an investigation by the European Union.
The European Commission last week said it would investigate the gas exporter over concerns it may be abusing its dominant position.
The decree requires strategic companies to obtain government approval to disclose information to foreign regulators, alter contracts or sell property abroad.
"We would like all questions that remain unclear for our partners in the European Commission to be cleared up as quickly as possible, so that we can work together smoothly," Mr Putin said.
"I hope that is how it will be."
The European Commission said last week its investigation would focus on suspicions that Gazprom was hindering the free flow of gas across 27 countries in Europe and imposing unfair prices on customers by linking the price of gas to oil prices.
Earlier, Mr Putin linked a recent investigation to the European debt crisis, accusing some European Commission officials of a desire to shift internal problems to Russia.
Gazprom subsidiaries in Europe were investigated by the EU a year ago.