Russia and Ukraine signed separate agreements with Turkey and the United Nations clearing the way for exporting millions of tons of desperately needed Ukrainian grain as well as Russian grain and fertiliser.
The moves end a wartime stand-off that had threatened food security around the globe.
Russian defence minister Sergei Shoigu and Ukrainian infrastructure minister Oleksandr Kubrakov signed separate deals with UN Secretary General Antonio Guterres and Turkish defence minister Hulusi Akar.
The ceremony was witnessed by Turkish President Recep Tayyip Erdogan.
“Today, there is a beacon on the Black Sea,” Mr Guterres said, “a beacon of hope, a beacon of possibility, a beacon of relief in a world that needs it more than ever.
“You have overcome obstacles and put aside differences to pave the way for an initiative that will serve the common interests of all,” he said, addressing the Russian and Ukrainian representatives.
The deal will enable Ukraine to export 22 million tons of grain and other agricultural products that have been stuck in Black Sea ports due to the war.
Ukrainian and Russian military delegations had reached a tentative agreement last week on a UN plan that would also allow Russia to export its grain and fertilisers.
Mykhailo Podolyak, an adviser to Ukraine’s president, stressed on Friday that Ukraine and Russia would sign separate agreements, saying Ukraine “does not sign any documents with Russia”.
Mr Guterres said the plan, known as the “Black Sea Initiative”, would open a path for significant volumes of commercial food exports from three key Ukrainian ports in the Black Sea: Odesa, Chernomorsk and Yuzhny.
It would “bring relief for developing countries on the edge of bankruptcy and the most vulnerable people on the edge of famine”.
“It will help stabilise global food prices which were already at record levels even before the war – a true nightmare for developing countries,” Mr Guterres added.
Ukraine is one of the world’s largest exporters of wheat, corn and sunflower oil, but Russia’s invasion of the country and naval blockade of its ports have halted shipments.
Some grain is being transported through Europe by rail, road and river, but the prices of vital commodities such as wheat and barley have soared during the nearly five-month war.
The deal makes provisions for the safe passage of ships. A control centre will be established in Istanbul, staffed by UN, Turkish, Russian and Ukrainian officials, to run and coordinate the process. Ships would undergo inspections to ensure they are not carrying weapons.
Foreign Secretary Liz Truss praised the efforts of Turkey and the UN to help reach a deal.
“Putin’s barbaric invasion of Ukraine has meant some of the poorest and most vulnerable people in the world are at risk of having nothing to eat.
“It is vital that Ukrainian grain reaches international food markets, and we applaud Turkey and the UN Secretary General for their efforts to broker this agreement,” she said.
“The UK and our allies have been pushing hard to reach this point.
“Now this agreement must be implemented, and we will be watching to ensure Russia’s actions match its words. To enable a lasting return to global security and economic stability, Putin must end the war and withdraw from Ukraine.”
Mr Podolyak insisted that no Russian ship would escort vessels and that there would be no Russian representative present at Ukrainian ports. Ukraine also plans an immediate military response “in case of provocations”, he said.
Mr Guterres first raised the critical need to get Ukraine’s agricultural production and Russia’s grain and fertiliser back into world markets in late April during meetings with Russian President Vladimir Putin in Moscow and Ukrainian President Volodymyr Zelensky in Kyiv.
He proposed a package deal in early June amid fears that the war was endangering food supplies for many developing nations and could worsen hunger for up to 181 million people.
Russian and Ukrainian officials have blamed each other for the blocked grain shipments.
Moscow accused Ukraine of failing to remove sea mines at the ports to allow safe shipping and insisted on its right to check incoming ships for weapons. Ukraine has argued that Russia’s port blockade and launching of missiles from the Black Sea made any shipments unviable.
Ukraine has sought international guarantees that the Kremlin wouldn’t use the safe corridors to attack the key Black Sea port of Odesa.
Ukrainian authorities have also accused Russia of stealing grain from eastern Ukraine and deliberately shelling Ukrainian fields to set them on fire.
In Washington, State Department spokesperson Ned Price said the US welcomes the agreement in principle.
“But what we’re focusing on now is holding Russia accountable for implementing this agreement and for enabling Ukrainian grain to get to world markets. It has been for far too long that Russia has enacted this blockade,” Mr Price said.