Erdogan and Putin held their first face-to-face talks in 18 months in the Black Sea resort of Sochi Wednesday, with the Syrian conflict high on their agenda.

"We had the opportunity to discuss what steps we could take on plane motors, warplanes," the Turkish leader told journalists on his return to Turkey.

"Another area where we can take several steps together is on building boats. We will God willing take joint steps even on submarines," he added, NTV broadcaster reported.

His comments will raise eyebrows in the West and especially in the United States, after Washington slapped sanctions on Turkey last year over its multi-billion-dollar purchase of the Russian-made S-400 air defence system.

The US also expelled Turkey from the F-35 programme under which Western allies produce the next-generation fighter jet's parts and secure its early purchasing rights.

Ankara was expecting as many as 100 of the stealth fighter jets, and multiple Turkish suppliers were involved in the construction.

Erdogan reaffirmed Turkey's commitment to the S-400, vowing Ankara "would not take a step back" from the purchase, but called on the US to either give the planes Turkey ordered or return its $1.4 billion payment.

Relations between Turkey and the US are strained, and Erdogan admitted last week that his personal ties with US President Joe Biden had "not gotten off to a good start".

Erdogan also said he proposed that Turkey and Russia could work together on building two more nuclear power plants, on which the Russian side agreed to cooperate.

Turkey's first nuclear power plant is under construction by Russia's Rosatom state nuclear energy firm in the country's south coast and it is expected to be online for Turkey's centenary as a post-Ottoman republic in 2023.

Despite Erdogan's warm words, the relationship between Turkey and Russia is complex, with the two countries on opposing sides in conflicts such as Libya and Syria.

Erdogan offered only vague comments on the two men's talks about northwestern Syria where regime troops and Moscow have increased airstrikes in recent weeks.

"We focused on the need to take steps together on the issue," Erdogan said.