The strikes were denounced by Oleg Nikolenko, a spokesperson for Ukraine’s foreign ministry, as a “spit in the face” of Turkish President Recep Erdogan and United Nations Secretary General António Guterres, who helped broker the deals.
“It took less than 24 hours for Russia to launch a missile attack on Odesa's port, breaking its promises and undermining its commitments before the U.N. and Turkey under the Istanbul agreement,” Nikolenko said in a statement.
“In case of nonfulfillment, Russia will bear full responsibility for a global food crisis,” he added.
President of Ukraine Volodymyr Zelenskyy said in a video address late Saturday that Russia has proven it can't be trusted to honor international agreements.
"Today's Russian missile attack on our port in Odesa — a cynical one," the president said. "It also turned out to be a blow to Russia's own political positions" because they can be undermined by broken deals, he argued.
Two missiles hit the port’s infrastructure and Ukrainian air defenses brought down two others, the Southern Command of Ukraine's military said in a statement. It did not specify whether there were any casualties or what damage was caused.
NBC News was not able to independently verify the claims.
Nikolenko called on the U.N. and Turkey to ensure that Russia complied with the commitments it made Friday.
These included the establishment of a maritime “humanitarian corridor” free of naval ships, warplanes and drones, to clear the way for the shipment of millions of tons of grain from Ukraine. It also released some Russian exports of grain and fertilizer held up by the war.
During a Friday signing ceremony in Istanbul, Guterres hailed the deal as “a beacon of hope, a beacon of possibility, a beacon of relief in a world that needs it more than ever.”
The deal was also supposed to establish a de facto cease-fire between Ukraine and Russia along identified shipping routes, and represented a big symbolic breakthrough.
U.S. Secretary of State Antony J. Blinken said in a statement Saturday that the attack erodes any global trust of Russia while threatening the global of food, the collapse of which will be blamed squarely on Moscow.
“Just 24 hours after finalizing a deal to allow the resumption of Ukrainian agricultural exports through the Black Sea, Russia breached its commitments by attacking the historic port from which grain and agricultural exports would again be transported under this arrangement,” Blinken said.
He added that the missile strike could shred the food deal just made.
“This attack casts serious doubt on the credibility of Russia’s commitment to yesterday’s deal and undermines the work of the UN, Turkey, and Ukraine to get critical food to world markets,” the secretary said.
Maria Zakharova, a spokesperson for Russia's foreign ministry, said in a statement that Russia had destroyed military infrastructure in the port.
The Russian blockade of Ukrainian ports has been in place since the invasion of the country on Feb. 24, triggering a food crisis around the globe. Before the war, Ukraine accounted for 10% of the world’s wheat exports, 14% of its corn and half its sunflower oil, and was known as the “breadbasket of the world.”
Although Russia blames the global food crisis on Ukraine and NATO, their argument has been losing traction in developing countries that rely heavily on Ukrainian grain and have experienced the brunt of the food crisis.
U.S. and E.U. sanctions against Russia have not banned food exports or targeted Russian fertilizer, but many private shipping and insurance companies have chosen not to do business with Moscow in the wake of the February invasion.
Elsewhere, in Ukraine's central Kirovohradska region, 13 Russian missiles struck an airfield and a railway facility.
Gov. Andriy Raikovych said that at least one serviceman and two guards were killed and the regional administration reported the strikes near the city of Kirovohrad, wounded another 13 people.
In the southern Kherson region, which Russian troops seized early in the invasion, Ukrainian forces were also preparing for a potential counteroffensive fired rockets at Dnieper River crossings to try to disrupt supplies to the Russians.
On Saturday, the U.S. State Department confirmed two Americans have died in the Donbas region of Ukraine. Their names and details regarding how they died were unavailable. NBC News has independently identified one of the U.S. citizens killed as Luke Lucyszyn.
An unknown number of people, mostly with military backgrounds, have traveled from the United States to Ukraine to help the nation in its quest to repel Russian forces. The State Department has repeatedly warned Americans not to go.