The leaders of Russia and Turkey have voiced support for the construction of a gas pipeline, a plan that was suspended amid tensions between the two countries.
In separate addresses to the World Energy Congress in Istanbul on Monday, Russian President Vladimir Putin and his Turkish counterpart Recep Tayyip Erdogan said their countries wanted to press ahead with the Turkish Stream project.
The pipeline would carry Russian natural gas to Turkey and on to European Union countries.
"We have been providing energy for the EU for the past 50 years," Putin said in his speech.
"We are now working on a second project. We are discussing the Turkish Stream with Erdogan and our other partners and we want to bring this about."
Erdogan said: "We look positively at the Turkish Stream project. Our efforts are continuing."
Putin was in Istanbul for the first time since Turkish-Russian relations were damaged last year when a Turkish fighter jet shot down a Russian warplane on the Syrian border.
Russia had responded by deploying long-range air defence missiles at its airbase in Syria, and imposing an array of economic sanctions on Turkey.
Relations improved after Erdogan apologised in June, but differences remain on Syria.
While Russia has backed Syrian President Bashar al-Assad throughout the nation's civil war and further bolstered that support by launching an air campaign last September, Turkey has pushed for Assad's removal and helped his foes.
In his speech on Monday in Istanbul, Putin also voiced support to Erdogan over the country's July 15 failed coup, saying he was happy that the country had "retained control" after the failed attempt.
"We are very glad that Turkey is recovering and wish it success," Putin said.
The two leaders are also expected to meet on the sidelines of the World Energy Congress to discuss economic ties and Syria.
"These are the first bilateral, direct talks that are to take place between Putin and Erdogan since the crisis over the downing of that jet," said Al Jazeera's Jamal Elshayyal, reporting from Istanbul.
"Both countries have realised after that falling out that they both stand to lose when they are not on good terms and they both stand to gain a lot when they are. And central to that is the energy trade between the two countries."
Turkey depends heavily on imports from Russia and it needs to ensure not only that it has that easy flow of energy coming through, but also it can capitalise on its geographic location as a bridge to Europe.
Putin had first suggested the Turkish Stream project to carry gas beneath the Black Sea into Turkey in 2014, when a pipeline project to Bulgaria fell through amid EU countries' opposition.
Russia is also building Turkey's first nuclear power station.
A senior Israeli government minister is also due to visit Turkey this week in the first such trip since the two countries normalised ties after a six-year crisis over Israel's deadly storming of a Gaza-bound ship.
Yuval Steinitz, Israeli energy minister, will attend the World Energy Congress in Istanbul on Thursday, the Israeli embassy in Ankara said in a statement.
"This is the first visit at ministerial level in the past six years, and it is the result of the rapprochement agreed upon by the two countries," it said.
Steinitz was due to hold talks with his Turkish counterpart Berat Albayrak - son-in-law of Erdogan - on the margins of the Istanbul summit.
The two men would discuss energy cooperation between the two countries, the embassy said.
At the congress, Steinitz is to deliver the opening remarks for an Atlantic Council panel titled A New Landscape in the Eastern Mediterranean, the statement added.
After his talks with Albayrak , Steinitz will hold a news conference.