Russia has stepped up attacks on Ukraine's grain export infrastructure amid talks on resumption of a Black Sea grain deal to allow unhindered exports of grain from Ukrainian ports.

One person was injured in the attack, the fourth on the key Danube river port in the last five days, Kiper said on the Telegram messaging app.

Ukraine's military reported shooting down 25 of the 33 drones it said were launched by Russia. Most were aimed at the Odesa region but some also targeted the northern area of Sumy, it added.

Russia quit the grain deal in July, a year after it was brokered by the U.N. and Turkey, saying its own food and fertiliser exports faced obstacles and insufficient Ukrainian grain was going to countries in need.

(Reporting by Reuters; Editing by Clarence Fernandez and Kim Coghill)