ODESA, Ukraine (AP) — President Volodymyr Zelenskyy visited one of Ukraine’s main Black Sea ports Friday, a week after a deal was struck with Russia, Turkey and the United Nations to create safe corridors for ships to export grains that have been trapped in the country since the war began five months ago.

His visit to a port in the Odesa region comes as workers were seen preparing terminals for grain exports, which are relied on by millions of impoverished people worldwide facing hunger.

“The first vessel, the first ship is being loaded since the beginning of the war,” Zelenskyy said.

He said the export of grain will begin with the departure of several ships that were loaded but could not depart the Ukrainian ports after the Russian invasion.

“Our side is fully prepared. We sent all the signals to our partners — the UN and Turkey, and our military guarantees the security situation,” he said, adding “it is important for us that Ukraine remains the guarantor of global food security.”

The visits to the ports are part of a broader push by Ukraine to show the world they are nearly ready to export millions of tons of grains to the world again after last week’s breakthrough agreement.

The complexities of the agreement and concerns about the safety of shipping crews has set the deal off to a slow, cautious start. It’s been a week since it was signed, and no grains have yet left ports. But the sides are facing a ticking clock — the deal is only good for 120 days.

It comes a week after Russian missiles struck Odesa, throwing into question Moscow’s commitment to the deal signed only hours earlier. The sides agreed to facilitate the shipment of Ukrainian wheat and other grains from Black Sea routes blocked by five months of war, as well as fertilizer and food from Russia.

The goal over the next four months is to get some 20 million tons of grain out of three Ukrainian sea ports blocked since the February 24 invasion. That provides time for about four to five large bulk carriers per day to transport grain from the ports to millions of impoverished people worldwide facing hunger.

“We are ready,” Ukraine’s minister of infrastructure, Oleksandr Kubrakov, told reporters at the port of Odesa on Friday.

But he said Ukraine is waiting on the UN to confirm the safe corridors that will be used by ships navigating the waters, which have been mined with explosives. In the meantime, a ship at the port of Chernomorsk was being loaded with grains, he said.

Martin Griffiths, the UN official who mediated the deal, said the first shipment of grains could depart Ukrainian ports as early as Friday but cautioned that work is still being done to finalize the exact coordinates of the safest routes, saying this must be “absolutely nailed down.”