The first official shipment of Ukrainian grain since Russia's invasion reached Turkish territorial waters on Tuesday near the entrance to the Bosphorus Strait, according to an AFP team on site.

The Sierra Leone-flagged Razoni is due to be inspected Wednesday near Istanbul by a team that includes Russian and Ukrainian officials before delivering its cargo of 26,000 tonnes of maize to Tripoli, Lebanon.

"The inspection of the ship by the joint inspection team will begin (Wednesday) morning," the Turkish defence ministry said.

The delivery, which set off from the Black Sea port of Odessa on Monday, is the first under a UN-backed deal brokered with the help of Turkey last month.

But Western-backed leaders in Kyiv accuse Russia of stealing Ukrainian grain in territories seized by Kremlin forces since their February invasion and then shipping it abroad.