Russia-Ukraine updates: US sanctions Russian military shipbuilder, diamond miner

Russia's Defense Ministry claimed Thursday that Ukraine violated regulations when placing sea mines in its territorial waters and that appropriate maps were not prepared.

Russia claimed these violations prevent foreign ships from being able "to safely leave the ports of Mykolaiv, Chernomorsk, Ochakiv, Odesa and Yuzhne and set out to open sea," Mikhail Mizintsev, the head of Russia's National Defense Control Center, claimed at a press briefing.

Mizintsev claimed 76 foreign ships from 15 countries remain blocked in Ukrainian ports.

Russia says in order for foreign vessels stuck at Ukrainian ports to depart safely, it has created a humanitarian corridor beginning Friday.

"The corridor will be operating daily between 8 a.m. and 7 p.m. (Moscow time) beginning from March 25, 2022," Mizintsev said. The corridor will be 80 nautical miles long toward the southwest with a navigation strip width of 3 miles.

Russia also said it evacuated 4,453 people from Mariupol without Kyiv's participation on Thursday.

In total, 86,718 people have already been evacuated from the city, Mizintsev claimed.

President Joe Biden said Thursday that G-7 leaders discussed the impact the war in Ukraine has had on food supply in European countries and the U.S., noting that both Ukraine and Russia “have been the breadbasket” of Europe and some of the largest producers of wheat.

“The price of these sanctions is not just imposed upon Russia, it’s imposed upon an awful lot of countries as well, including European countries and our country as well,” he said.

The president said he urged European leaders to end trade limitations on sending food abroad in order to alleviate the food shortage, highlighting that the U.S. and Canada are also large producers of wheat.

“We are in the process of working out with our European friends what it would be -- what it would take to help alleviate the concerns relative to food shortages. We also talked about a significant major U.S. investment among others, in terms of providing for the need for humanitarian assistance, including food, as we move forward,” Biden said.

-ABC News' Armando Garcia

Defense Secretary Lloyd Austin told the Ukrainian minister of defense, Oleksii Reznikov, on Thursday that security assistance from the U.S. is now flowing into the region.

This includes aid from the $1 billion in security assistance recently announced by President Joe Biden, according to Pentagon press secretary John Kirby.

-ABC News' Matthew Seyler

British Prime Minister Boris Johnson on Thursday said consequences would be "very, very severe" if Vladimir Putin deploys chemical weapons.

"I think it would be catastrophic for him if he were to do that. And I think that he understands that," Johnson said.

He added that he thinks Biden was right in saying Putin's comments are a "clear sign" Russia is weighing the use of chemical weapons.

"I think [President] Joe Biden is right to warn ... because you know, when the Russians start doing this stuff about, 'oh, well … the factories in Ukraine producing American biological weaponry,' you know that is a prelude to a false flag operation and they could well do something, but I think it will make a profound and a disastrous mistake for Putin."

-ABC News' Christine Theodorou