Russia-Ukraine updates: Putin suspends key US-Russia nuclear treaty in speech denouncing West

The Russian Foreign Ministry issued a warning to nations with nuclear capabilities, calling on them to abandon attempts to infringe on each other's vital interests, warning that direct armed conflict and provocations with weapons of mass destruction can lead to catastrophic consequences.

Russia claimed it believes there can be no winners of nuclear war and said it refarrims its commitment to the prevention of nuclear warm.

"A reaction with the use of nuclear weapons is hypothetically allowed by Russia only in response to aggression using weapons of mass destruction or aggression using conventional weapons, when the existence of the state is threatened," the ministry said in a statement.

The White House has said it will not confirm or deny New York Times reporting that senior Russian military officials had recently discussed when and how Russia might use a tactical nuclear weapon in Ukraine. The intelligence about the conversations was reportedly circulated inside the U.S. government in mid-October.

But, Russian President Vladimir Putin was not a part of these alleged conversations, according to the New York Times.

The White House on Wednesday said it still sees "no indications that Russia is making preparations" to use nuclear weapons.

-ABC News' Natalia Shumskaia and Ben Gittleson

Turkish Recep Tayyip Erdogan announced Wednesday that Russia has agreed to resume its participation in a deal brokered by Turkey and the United Nations to keep grain and other commodities shipping out of Ukraine's ports amid the ongoing war.

Russian Defense Minister Sergei Shoigu informed his Turkish counterpart, Hulusi Akar, that the so-called Black Sea Grain Initiative would "continue in the same way as before" as of noon Wednesday, according to Erdogan.

The renewed agreement, first reached over the summer, will prioritize shipments to African countries, including drought-ravaged Somalia, after Russia expressed concerns that most of the grain was ending up in richer nations.

Moscow agreed to return to the deal after receiving written guarantees from Kyiv that Ukraine would not use the safe shipping corridors through the Black Sea for military actions against Russian forces, according to the Russian Ministry of Defense.

Russia had suspended its role in the deal over the weekend, after accusing Ukrainian forces of carrying out a "massive" drone attack on its Black Sea fleet on Saturday.

Turkey and the U.N. brokered separate deals with Russia and Ukraine in July to allow Ukraine to resume its shipment of grain from the Black Sea to world markets and for Russia to export grain and fertilizers.

Since Russian forces invaded neighboring Ukraine on Feb. 24, the cost of grain, fertilizer and fuel has skyrocketed worldwide. Russia and Ukraine -- often referred to collectively as Europe's breadbasket -- produce a third of the global supply of wheat and barley, but a Russian blockade in the Black Sea combined with Ukrainian naval mines have made exporting siloed grain and other foodstuffs virtually impossible. As a result, millions of people around the world -- particularly in Africa and the Middle East -- are now on the brink of famine.

Iranian ballistic missiles, which Russia plans to purchase from Iran, will probably be placed on the northern border of Ukraine, the spokesman of the Ukrainian Airborne Forces Yuri Ignat said Tuesday.

Ignat claimed the ballistic missiles' range was 300 km for one and 700 km for another.

"We have no effective defense against these missiles. It is theoretically possible to shoot them down, but in fact it is very difficult to do it with the means we have at our disposal. We have air defense, not missile defense," he said.

-ABC News' Yulia Drozd

As Ukrainian forces advance to capture the city of Kherson, Russian forces are ordering civilians out of parts of the now-occupied city. Some 70,000 people along a 15 kilometer (10 mile) stretch of the left bank of the Dnipro River will be evacuated deeper into the Kherson region or to Russia, according to the Russian-installed leader of the occupied Kherson region, Vladimir Saldo.

Russia had previously ordered civilians out of an area it controls on the west bank of the river.

-ABC News' Will Gretsky