ISTANBUL (AP) — Russian President Vladimir Putin is set to meet Turkish President Recep Tayyip Erdogan in Istanbul as the two leaders push toward normalizing ties that were strained by Turkey's downing of a Russian warplane near the border with Syria last year.

Putin is scheduled to meet Erdogan Monday on the sidelines of the World Energy Congress.

The two are expected to advance joint energy projects, including Russian plans for a natural gas pipeline, called "Turkish Stream," that would carry gas beneath the Black Sea to Turkey and to European markets. Russia is also building Turkey's first nuclear power station.

Differences remain on Syria. While Moscow has backed Syrian President Bashar Assad throughout the nation's civil war, Turkey has pushed for Assad's removal and helped his foes.