Samantha Power, director of the US Agency for International Development, said the United States is working with Ukraine on a “Plan B” (Plan B) to stop grain exports from the country following Russia’s attack on the port of Odessa.

“The alternative plan includes road, rail, river and sea transportation, as well as adjusting rail systems to better match European ones so exports can move faster,” Power told CNN. She called on “countries that play a leading role in the international system to work harder to ensure that the food crisis does not turn into a catastrophe.”

On Friday, the Russian and Ukrainian authorities signed an agreement allowing the export of Ukrainian grain through the Black Sea, after months of difficult negotiations brokered by Turkey and the UN. However, just a day later, Russia launched a missile attack on the southern Ukrainian port of Odessa, where the main grain reserves are stored.