Russian President Vladimir Putin and his Turkish counterpart, Recep Tayyip Erdogan, signed an agreement on Monday to build the Turkish Stream natural gas pipeline to carry Russian gas to south-eastern Europe.
"The agreement provides for the construction of two lines of the main pipeline across the bottom of the Black Sea," the head of Russia's gas export monopoly, Gazprom, said in comments carried by Russian state news agency TASS.
The lines should be built by the end of 2019, Gazprom CEO Alexei Miller said. The pipeline is planned to carry Russian gas to Turkey and possibly European Union member state Greece.
Putin was in Istanbul to address the World Energy Congress and meet with his Turkish counterpart as their countries repair damaged relations.
In a speech to the World Energy Congress, Putin said earlier that Russia was ready to join members of the Organization of Petroleum Exporting Countries (OPEC) in limiting production of crude oil, as exporters look to prop up prices for the commodity.
"We believe that a freeze or even a reduction in the production of oil is probably the only appropriate decision for maintaining [the] sustainability of global energy," Putin said in comments carried by TASS.
Earlier this year, Russia and OPEC's de facto leader, Saudi Arabia, the world's two largest oil suppliers, made a conditional pledge to limit oil production.
That pledge contributed to some price growth but failed to significantly reverse a rout that has devastated oil-dependent economies in recent years.
"A production freeze can at best only support the price of Brent [crude oil] at around 50 US dollars per barrel" where it is currently trading, said Chris Weafer, senior partner at Russian-focused investment consultancy Macro Advisory, in a Monday note to investors.
It was Putin's first time in Istanbul since Turkish-Russian relations were frayed last year when a Turkish fighter jet shot down a Russian warplane on the Syrian border.
The conflict in Syria, where Russia and Turkey support opposing sides, figured in a private conversation between the leaders on Monday, Putin said in comments to the press.
In a further sign of reviving relations, Turkey announced on Sunday that it agreed to sign a deal to create a billion-dollar investment fund with Russia to "boost relations in many areas, such as tourism, energy, agriculture and transport," Turkish state news outlet Anadolu Agency reported.