Wheat rose from the lowest level since early June as hostilities between Ukraine and Russia ramped up again in the key Black Sea waterway.

Futures in Chicago gained as much as 0.7% on Wednesday after losing more than 6% over the previous four sessions. A military plane destroyed four speed boats with Ukrainian soldiers in the Black Sea, Russia’s Ministry of Defense said in a Telegram post. Tass also reported a drone attack near Sevastopol.

Conflict has escalated in the Black Sea this month after Moscow pulled out of a grain deal in July that ensured the safe passage of Ukrainian grain. Benchmark wheat futures are still about 24% lower this year following bumper harvests in some parts of the Northern Hemisphere.