The United Nations says that no grain ships will leave Ukrainian ports on Wednesday

Three grain ships set sail from Ukraine’s Black Sea ports on Tuesday, but the United Nations said that no vessels would be leaving the next day, raising questions about how long the safe passage deal brokered by the United Nations and Turkey could continue after President Vladimir V. Putin of Russia suspended Moscow’s participation.

Moscow made the announcement after blaming Ukraine for an attack over the weekend on its Black Sea naval fleet, and the Kremlin said in a statement on Tuesday that it would consider resuming the deal only after a “a detailed investigation.” President Recep Tayyip Erdogan of Turkey spoke with Mr. Putin on Tuesday and said he was “confident” that differences over the grain deal could be resolved, according to a statement from the Turkish leader’s office.

The three cargo ships, carrying corn, wheat and sunflower oil, respectively, were sailing south toward Istanbul, according to VesselFinder.com and Ismini Palla, a U.N. spokeswoman. She said that the Russian authorities had been notified of the departures. The United Nations later said that the Ukrainian, Turkish and United Nations delegation agreed not to plan any ship movements for Wednesday, but did not give further details.

Russia’s Navy is a dominant presence in the Black Sea and Moscow’s full-scale invasion in February prevented Ukraine, a major exporter of grain and other agricultural products, from shipping its produce. Global prices rose sharply, in part because of the war, making grain purchases even more expensive for the dozens of countries around the world that already faced food shortages.

The deal signed in July offered hope, by unblocking those Ukrainian supplies. Aid groups warned that Russia’s decision over the weekend could worsen the situations for countries including Yemen, Afghanistan and Somalia, but on Tuesday wheat prices, which had risen sharply on Monday when trading opened, remained broadly flat.

Under the terms of the deal, empty ships are inspected in Istanbul before they depart for Ukraine to check that they are not carrying weapons, among other things. Once they leave Ukraine, they go through Istanbul loaded with grain, and are inspected again before heading to their destinations.

On Monday, 46 empty vessels were inspected.— after Russia’s announcement — and the ships were “cleared to sail,” Ms. Palla said. Inspections of empty vessels also continued on Tuesday.

Twelve cargo vessels carrying grain sailed without incident from Ukraine’s ports and were off the Turkish coast on Tuesday.

Speaking at a news conference on Monday in Sochi, Russia, Mr. Putin said that the onus was on Ukraine to guarantee the ships’ safety, but he did not rule out the possibility that Russia would honor the grain deal again.

“We are not saying that we are stopping our participation in this operation,” Mr. Putin said. “We are saying that we are pausing it.”

Tags: ships, Black Sea ports, Ukraine, Russia, sunflower oil, corn, Turkey, grain, wheat, United Nations, vessels