Stjepan Mesic, the Croatian president, met with Russian Prime Minister Vladimir Putin in Moscow to discuss the South Stream natural gas pipeline.
The pipeline would bring natural gas from Central Asia and Russia to the Balkans and other European customers along a route that avoids Ukraine. Turkey recently approved preliminary steps for South Stream construction in the Black Sea as the intended route develops.
Mesic said the ruling government in 2007 rejected Putin's offer to sign on to the South Stream project, Serbian news outlet B92 reports.
"We missed that discussion when the time was right," he said.
He added any cooperation in the project would rely on goodwill gestures from Moscow, though he lamented that he "does not have high hopes."