Russian officials have warned Ukrainians in occupied Kherson that they may be "deported" if they don't accept Russian passports, the U.K. Ministry of Defence said Monday.

"Russia is using passports as a tool in the 'Russification' of the occupied areas, as it did in Donetsk and Luhansk before the February 2022 invasion," the ministry on Twitter.

Residents of Kherson have been warned of penalties for those who don't accept Russian passports by June 1. Some may be removed from the territory or may have their property seized, according to the U.K.

Russia said Sunday that the U.S. has denied visas to Russian journalists who wanted to cover Foreign Minister Sergey Lavrov's trip to New York.

Lavrov promised that the decision will not be forgotten by their side.

"The country that calls itself the strongest, smartest, most free, fairest has chickened out, has done a silly thing and shown what its sworn assurances on protecting freedom of speech, access to information and so on are worth," he told reporters at the airport before his flight to New York.

"Most importantly, you can be sure: we will not forget, we will not forgive this," the minister told the pool of journalists who have not been granted U.S. visas.

The journalists had planned to cover Lavrov's appearance at the United Nations to mark Russia's chairmanship of the Security Council.

Russian Deputy Foreign Minister Sergei Ryabkov called the U.S.’s decision “outrageous” on Sunday, Interfax, a Russian news agency, reported.

There was no immediate comment from the U.S. State Department about the claim of refused visas, according to AP.

-ABC News’ Anastasia Bagaeva, Edward Szekeres, Natalia Shumskaia

Over 16,000 Ukrainian soldiers trained in the European Union, Josep Borrell, an EU representative for Foreign Affairs and Security Policy, said Friday.

The EU has delivered over $600 million of ammunition and missiles to Ukraine, according to Borrell.

-ABC News' Oleksiy Pshemyskiy

The Russian Defense Ministry reported that ammunition from a Russian Su-34 military aircraft fell in Belgorod, a city in the southern region of Russia.

"On the evening of April 20, during the flight of the Su-34 aircraft over the city of Belgorod, an abnormal descent of an aviation munition occurred," the agency said.

The ministry claimed buildings were damaged but there were no immediate reports of victims. An investigation is underway, according to the agency.

-ABC News' Will Gretsky

U.S. Secretary of State Antony Blinken urged the Kremlin to release imprisoned Wall Street Journal reporter Evan Gershkovich in a phone call Sunday with his Russian counterpart, according to a State Department spokesperson.

Blinken spoke with Russian Foreign Minister Sergey Lavrov, conveying the United States' "grave concern" over the "unacceptable detention" of a U.S. citizen, according to Vedant Patel, a deputy spokesperson for the State Department.

"The secretary called for his immediate release. Secretary Blinken further urged the Kremlin to immediately release wrongfully detained U.S. citizen Paul Whelan," said Patel, referring to the American held in Russia on espionage charges since 2018.

According to a read out of the phone call released by the Kremlin, Lavrov emphasized that Gershkovich "was taken red-handed while trying to obtain classified information, collecting data constituting a state secret under the guise of journalistic status."

"In the light of the established facts of illegal activity of a U.S. citizen, of whose detention the U.S. Embassy in Moscow was notified in accordance with the established procedure, his further fate will be determined by the court," the Kremlin said in a statement.

The Kremlin said that during the conversation, Lavrov emphasized officials in Washington and the Western media are "escalating the hype with the clear intention of giving this case a political coloring."

Blinken and Lavrov also spoke of the "importance of creating an environment that permits diplomatic missions to carry out their work," according to Patel.