Russian energy company Rosneft said it signed agreements with its Brazilian counterparts to help sell natural gas locked in the Amazon forest.

Russian President Vladimir Putin and his Brazilian counterpart, Dilma Rousseff, led the signing ceremony for a memorandum of understanding for the monetization of natural gas from the Solimoes projects in the Brazilian jungle.

"The memorandum envisages detailed analysis of options for monetization of gas held in the Solimoes basin, creation of a joint work group and preparation of roadmap for progressing the study," Rosneft said in a statement Monday.

The memorandum was signed between Rosneft, state-run Petroleo Brazileiro and oil and gas company HRT, controlled in part by the Russian company.

The Brazilian National Agency of Petroleum in 2012 said the region holds an estimated 2.4 billion barrels of oil equivalent in proven reserves.

In a related move, the Brazilian government approved the assignment of another 6 percent of the working interest in the Solimoes basin from HRT's portfolio to the Brazilian subsidiary of Rosneft. That gives Rosneft a controlling stake in the project.

That transaction was valued at $96 million.