STORY: Russian missiles hit Ukraine's major port Odesa on Saturday (July 23), Ukraine's military has said - only a day after a deal was signed to try and unblock grain exports across the Black Sea.
The landmark agreement signed between Moscow and Kyiv on Friday (July 22) is seen as crucial to curbing soaring global food prices.
U.N. officials said they hoped the agreement would be operational within a few weeks.
But it was not yet clear if that would still be possible given Saturday's reported strikes.
Nataliia Humeniuk, spokeswoman for Ukraine's Operation Command "South", said there was no "significant" damage from the strikes or casualties.
he said two missiles hit infrastructure and two were intercepted by Air Defense forces.
Ukraine's foreign ministry called on the United Nations and Turkey, which mediated the grain deal, to ensure Russia fulfils its commitments and allows free passage in the grain corridor.
U.N. Secretary-General Antonio Guterres said "unequivocally condemns" the reported strikes.
Turkey's defense minister said Russia had told Ankara it had nothing to do with this attack, and were examining the issue "very closely and in detail".
A blockade of Ukraine's ports by Russia's Black Sea fleet since Moscow's February 24 invasion has trapped tens of millions of tons of grain.
With Russia and Ukraine both major global wheat suppliers, food prices have soared.
The crisis has pushed some 47 million people into "acute hunger" according the World Food Programme.
Russia, which called its invasion a "special military operation", has denied responsibility.
It blames Western sanctions for slowing its own food and fertilizer exports and Ukraine for mining the approaches to its Black Sea ports.
Under Friday's deal, Ukrainian officials would guide ships through safe channels across the mined waters to three ports, including Odesa, where they would be loaded with grain.
Ukrainian President Volodymyr Zelenskiy said on Friday the deal would make around $10 billion worth of grain available for sale with roughly 20 million tons of last year's harvest to be exported.