The cargo ships carrying over 160,000 tonnes of corn and other foodstuffs left Chernomorsk and Odesa, heading for Turkey, Italy and China under an international deal struck in July.
Four ships carrying Ukrainian foodstuffs set sail from Ukrainian Black Sea ports on Sunday as part of a deal to unblock the country's sea exports, Ukrainian and Turkish officials said.
The four bulk carriers were loaded with almost 170,000 tonnes of corn and other foodstuffs, Ukraine's sea ports authority said on Facebook.
The body overseeing the operation said on Saturday evening that it had authorised the departure of a total of five new vessels through the Black Sea corridor: four vessels outbound from Chernomorsk and Odesa, and one inbound.
The Joint Coordination Centre (JCC) said that in total, the outbound ships would carry more than 161,000 tonnes of corn and food products to Turkey, China and Italy.
Their progress will be monitored to Istanbul, where they will be inspected offshore before sailing through the Bosphorus.
With these new departures, Ukrainian grain exports are gradually finding a regular rhythm.
"Schedules may be affected by preparations and weather conditions or any other unforeseen circumstances," the JCC said in a statement.
At the same time, the centre has given permission for the MV Osprey cargo ship to sail, empty, to Chernomorsk as soon as it has been inspected on Sunday off Istanbul.
The JCC is established in Istanbul under the terms of the international agreement signed on 22 July between Russia, Ukraine, Turkey and the United Nations.
This agreement frees up Ukrainian grain exports blocked by the war since 24 February and Russian agricultural products, despite Western sanctions.
On Saturday evening, experts completed the inspection of the Navistar, which left Odesa on Friday for Ireland.
Two other ships that left at the same time will be inspected on Sunday, the JCC said.
Ukraine's President Volodymyr Zelenskyy welcomed the revival of Ukrainian agricultural exports by sea. "Our Black Sea ports are working," he said in his address to Ukrainians on Saturday evening.
"But the main risk, security, remains. The danger of Russian provocation and terrorist acts remains. Everyone must be aware of this. But if our partners fulfil their obligations and guarantee the security of deliveries, this will solve the global food crisis," he added.