The hopes of developing nations that desperately need the grain to avoid worsening food shortages were jeopardized by Russia's firing missiles on the Black Sea port of Odessa on Saturday.
Russia and Ukraine signed an agreement in Istanbul on Friday that will allow millions of tons of Ukrainian grain to be exported.
Ukrainian President Volodymyr Zelenksy said the attack proves that no matter what Russia says and promises, it will not implement it.
The attack was denounced by the U.S. ambassador to Ukraine.
The EU said the strike was reprehensible and represented another example of Russia's disregard for international law.
There is no enforcement system in place to make sure the safe passage of grain. According to the Washington Post, it could take weeks before a place is in place.
There was an attack on the port but not the grain silos.
Although it is one of the world's leading grain exporting countries, the blockade has prevented it from shipping its product. A global food shortage has resulted in a huge surplus of grain remaining inUkraine. The country has been accused of stealing hundreds of thousands of tons of Ukrainian grain products, which is critical to the economy of the country.
There are 25 million tons. The amount of grain trapped in Ukraine is not known.
There is a deal with Russia to resume grain exports.
The Washington Post reported that missiles were fired at the port on the day after the grain deal.