There is a "high" possibility that the first ship carrying grain could leave Ukraine’s Black Sea ports as soon as Monday, a senior Turkish official said, as preparations neared completion to resume shipments of the crucial commodity that has been trapped since the war began five months ago.

Ukraine’s President Volodymyr Zelenskyy on Friday said Kyiv was ready to start exporting grain under a United Nations-led plan, aimed at freeing up blocked Black Sea ports and easing global food shortages, and was awaiting the signal for the first shipment.

"If all (details) are completed by tomorrow, it seems like there is a high possibility that the first ship will leave the port tomorrow ... We will see ships leaving the ports the next day at the latest," Turkish Presidential Spokesperson Ibrahim Kalın said on Sunday.

Kalın said there were "one or two details to be settled in the negotiations with the Russians."

"Preparations have reached a point to allow the ships to leave the port of Odessa. The ships have been loaded, they are ready to leave, but we need good logistical coordination," he told an interview with broadcaster Kanal 7.

Zelenskyy on Friday paid an unannounced visit to the port of Chernomorsk near the southern city of Odessa to oversee the first grain being loaded onto a Turkish ship. And workers were seen preparing terminals for commodity exports, which are relied on by millions of impoverished people worldwide facing hunger.

Ukraine is a key global exporter of wheat, barley, corn and sunflower oil, and their loss has raised global food prices, threatened political instability and helped push more people into poverty and hunger in already vulnerable countries.

The breakthrough agreements, which were brokered by Turkey and the U.N. and signed separately by Moscow and Kyiv in Istanbul on July 23, are intended both to ease the food crisis and reduce global grain prices.

The sides agreed to facilitate the shipment of wheat and other grains from three Ukrainian ports through safe corridors on the Black Sea, as well as fertilizer and food from Russia.

The agreements aim to allow safe passage for shipments in and out of Chernomorsk, Odessa and the port of Pivdennyi.

Ukraine ‘fully’ prepared

Presidential officials said there were 17 ships docked in Ukraine’s Black Sea ports with almost 600,000 tons of cargo. Of them, 16 vessels are said to hold Ukrainian grain with a total tonnage of about 580,000 tons.

The departure of wheat and other grain will begin with ships that were already loaded but could not leave Ukrainian ports after Russia invaded, Zelenskyy said.

"Our side is fully prepared. We sent all the signals to our partners – the U.N. and Turkey, and our military guarantees the security situation," Zelenskyy said.

Ukrainian officials on Friday said Chernomorsk and Odessa were ready to start shipping grain and expressed hopes that Pivdennyi would be ready by the end of the week.

The deal stipulates that Russia and Ukraine will provide "maximum assurances" for ships that brave the journey through the Black Sea to the Ukrainian ports.

For ships heading to Ukraine’s three ports, smaller Ukrainian pilot boats will guide the vessels through approved corridors.

The entire operation will be overseen by a joint coordination center (JCC) in Istanbul staffed by officials from Ukraine, Russia, Turkey and the U.N.

Once ships reach port, they will be loaded with tens of thousands of tons of grains before departing back to the Bosporus, where they will be boarded to inspect for weapons. Ships embarking to Ukraine will also likely be subject to inspections.

Turkey-Ukraine talks

Separately, Turkish Defense Minister Hulusi Akar on Sunday held phone calls with Ukraine’s defense and infrastructure ministers to discuss the latest developments regarding the shipments, his ministry said in a statement.

In talks with his Ukrainian counterpart Oleksii Reznikov and Infrastructure Minister Oleksandr Kubrakov, the officials exchanged views on the activities conducted at the JCC.

They said technical work on the shipment of grain was completed and Ukrainian grain shipment is expected to start at the earliest after administrative preparations conclude, according to the statement.

Kalın on Sunday said the monitoring center in Istanbul will probably complete the final work on the exporting routes very soon.

Harvest could be halved by war

The goal over the next four months is to export some 20 million tons of grain from three Ukrainian sea ports blocked since the Feb. 24 invasion.

Getting wheat and other food out is also critical to farmers in Ukraine, who are running out of storage capacity amid a new harvest. Those grains are vital to millions of people in Africa, parts of the Middle East and South Asia, who are already facing food shortages and, in some cases, famine.

Zelenskyy on Sunday warned that Ukraine’s harvest could be half its usual amount this year due to the invasion. "Ukrainian harvest this year is under the threat to be twice less," suggesting half as much as usual, he wrote in English on Twitter.

"Our main goal — to prevent global food crisis caused by Russian invasion. Still grains find a way to be delivered alternatively," he added.