After Russia threatened to escalate the war in Ukraine and there is the possibility of further disruption to global grain supplies via the Black Sea, wheat futures rose for the third consecutive day.

According to Bloomberg, the most-traded wheat contract in Chicago rose by up to 1% on Monday before giving back some of its gains. The commodity is now going through the longest upward run of the past month.

On Sunday, Russia’s Ministry of Defense said it would intensify its attacks on Ukrainian infrastructure.

Based on the same report, wheat supply from the Black Sea—one of the world’s largest commercial corridors for this product—has been severely restricted since July.

Further escalation could make Turkey’s efforts to protect grain shipments in the region more difficult.

In a note published on Friday, the CRM Agri Commodities Institute wrote: “Turkey’s mediation may finally get the shipments back, but an agreement could take months. Progress removes risk, while continued disruption supports prices.”

Russian wheat exports last month fell by 75% compared with the same period a year earlier.