Turkish President Recep Tayyip Erdogan called on Sunday for Russia not to be "marginalised" in talks aimed at reviving a key deal to export Ukrainian grain through the Black Sea.

"No process that marginalises Russia on the Black Sea grain initiative will be viable," Erdogan told reporters after the close of the G20 summit in New Delhi.

He announced a forthcoming meeting on the issue between representatives from Russia, Ukraine and the United Nations, without specifying a precise date or location.

The UN- and Turkey-brokered grain deal, which aimed to ensure safe navigation for civilian ships through the Black Sea, collapsed after Russia pulled out in July.

Moscow has since repeatedly attacked Ukraine's port infrastructure, in what Kyiv says is a cynical attempt to damage its exports and undermine global food security.

A Russian drone attack on Monday hit a grain export hub on the Danube river, officials said, adding that warehouses and agricultural equipment had been damaged.

Hours later, Russian President Vladimir Putin met Erdogan in Sochi, amid hopes the two could restore the deal.

Erdogan had said he would make a "very important" announcement on grain exports after the talks.

"I know you intend to raise the issue of the grain deal. We are open to negotiations on this issue," Putin said in televised comments, speaking alongside Erdogan.