• Millions of tonnes of grain have been stuck in Ukraine due to Russian blockades, leading to shortages and higher food prices in other countries.
• The latest ships to set sail are bound for Turkey where they'll be inspected as part of a deal reached with Russia and the United Nations.
Four more ships carrying grain and sunflower oil have left Ukraine ports via a safe maritime corridor.
Millions of tonnes of grain have been stuck in Ukraine due to Russian blockades, leading to shortages and higher food prices in other countries.
But last week the first ship left Ukraine's ports since February.
The latest ships to set sail are bound for Turkey where they'll be inspected as part of a deal reached with Russia and the United Nations.
They left on Sunday from the ports of Odesa and Chornomorsk, and will all travel through the Bosphorus strait.
After the inspections, two are then scheduled to dock in Turkey, while the others are headed for Italy and China.
Another empty ship arrived in Chornomorsk on Sunday afternoon, ready to be loaded with grain for export.
Under a deal brokered by Turkey and the UN last month, Russia agreed not to target ships which were in transit, while Ukraine said it would guide vessels through mined waters.
The deal, set to last 120 days, can be renewed if both sides agree.
The complex arrangement seems to be working, at least for now.
The success of this deal, a rare diplomatic breakthrough in this five-month-old conflict, is vital for Ukraine - and the rest of the world.
Twenty million tonnes of grain are stuck in the country, as a result of the blockade imposed by Russia on Ukrainian ports. If the deal holds, Ukraine expects to export up to three million tonnes of grain per month.
Ukrainian authorities say there are good signs that the grain exports are safe, and have urged companies to return to the country's ports. The hope is that the exports will help ease the global food crisis while bringing in much needed foreign currency.
But fears persist. Ukraine's President Volodymyr Zelensky welcomed the resumption of exports, but said security concerns remained.
The first ship to leave Ukraine last week - the Razoni - departed Odesa carrying 27,000 tonnes of corn bound for the Lebanese port of Tripoli.
However officials have said it will not dock in Tripoli on Sunday as planned.
The Ukrainian embassy in Lebanon told Reuters news agency on Sunday that the ship was "delayed", with no details on the cause or an updated arrival date.
A Joint Coordination Centre which was set up to oversee the exports said the Razoni's voyage would be a trial run, with its experience used to fine-tune procedures for the following voyages.