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The Mayor of Mariupol — now under Russian control — says "the ‘occupiers’ have buried at least 16,000 residents in mass graves in nearby villages," according to a report by

Latest Developments in Ukraine: May 30

U.S. National Security Advisor Jake Sullivan spoke by phone with his Turkish counterpart, Ibrahim Kalin, spokesperson and chief adviser to President Recep Tayyip Erdogan,

Latest Developments in Ukraine: May 30

"They discussed their ongoing support for Ukraine in the face of Russia’s continued aggression, as well as their respective efforts to enable Ukrainian agricultural exports to reach global markets," the statement said. "Mr. Sullivan expressed support for Turkey’s continued direct talks with Sweden and Finland to resolve concerns over their applications for NATO membership, which the U.S. strongly supports."

Latest Developments in Ukraine: May 30

Alan Gagloev, the leader of Georgia's breakaway region of South Ossetia, scrapped plans to hold a referendum on joining Russia that his predecessor had scheduled for July 17, Agence France-Presse reported. South Ossetia was at the center of the Russian-Georgian war in 2008 after which the Kremlin recognized the territory as an independent state and stationed military bases there, AFP reported.

In a decree issued Monday, Gagloev invoked "uncertainty of the legal consequences of the issue submitted to a referendum,” AFP reported. He also ordered "to hold, without delay, consultations with the Russian side on the entire range of issues related to the further integration of South Ossetia and the Russian Federation.”

Ukrainian President Volodymyr Zelenskyy said the Russian blockade of Ukrainian sea ports prevents Kyiv from exporting 22 million tons of grain, The Associated Press reported. Zelenskyy said the result is the threat of famine in countries dependent on the grain and could create a new migration crisis, AP reported. He charges that “this is something the Russian leadership clearly seeks.”

In the AP report, Zelenskyy accuses Moscow of “deliberately creating this problem so that the whole of Europe struggles and so that Ukraine doesn’t earn billions of dollars from its exports.”

European Union leaders said they had agreed to cut 90% of oil imports from Russia by the end of this year, resolving an impasse over the bloc's toughest sanction yet on Moscow since the invasion of Ukraine three months ago, Reuters reported. Diplomats said the agreement would clear the way for other elements of a sixth package of EU sanctions on Russia to take effect, including cutting Russia's biggest bank, Sberbank, from the SWIFT messaging system, Reuters reported.

"Agreement to ban export of Russian oil to the EU," said European Council President Charles Michel in a tweet at the end of the first day of a two-day summit of the bloc's 27 leaders,accordign to Reuters. "This immediately covers more than 2/3 of oil imports from Russia, cutting a huge source of financing for its war machine. Maximum pressure on Russia to end the war.”

U.S. President Joe Biden said the United States would not supply Ukraine with long-range rocket systems that can reach into Russia, Radio Free Europe/Radio Liberty reported. News reports last week said the Biden administration was leaning toward sending such systems, which Ukrainian government officials have sought for the fight against Russia.

"We're not going to send to Ukraine rocket systems that can strike into Russia," Biden told reporters as he returned to Washington from his home in Delaware.

Two systems -- the Multiple Launch Rocket System, or MLRS, and the High Mobility Artillery Rocket System, known as HIMARS -- were under consideration, according to CNN and The Washington Post on Saturday.

In his nightly video address, Ukrainian President Volodymyr Zelenskyy discussed Europe and Russia oil sanctions. “The key point is, of course, the oil. I believe that Europe will have to give up Russian oil and oil products in any case. Because this is about the independence of Europeans themselves from Russian energy weapons. And the sooner this happens, the more complete the abandonment of Russian oil will be, the greater the benefit will be for Europe itself in the end,” Zelenskyy said.

France called for an investigation after Frederic Leclerc-Imhoff, 32, a French journalist, was killed in Ukraine when the vehicle he was traveling in, which was being used to evacuate civilians near the city of Sievierodonetsk, was hit by shelling, Reuters reported. "France demands that a probe be carried out as soon as possible and in transparency on the circumstances of this drama," Foreign Minister Catherine Colonna, who was in Ukraine on Monday, said in a statement.