Russia and Ukraine just turned much of the Black Sea into a dangerous no man's land

• Russia and Ukraine have exchanged threats this week to ships sailing through the Black Sea.
• Both sides warned that they will consider any vessel in the area to be a carrier of military cargo and a legitimate target.

Russia and Ukraine threatened to militarize the Black Sea by warning they could target vessels sailing through the strategic body of water, a dangerous escalation that jeopardizes the safety of commercial vessels and risks drawing other nations into the bloody conflict.

The move from both sides comes shortly after Russia killed the crucial Black Sea grain deal, a United Nations-brokered agreement that allowed Ukraine to export food and fertilizer from several key ports to avoid a global food crisis. The Kremlin then went much further, warning it may attack any vessels it believes are bound for Ukraine, effectively turning the Black Sea into a no man's land.

Moscow withdrew from the deal on Monday and immediately started to ramp up its attacks on Ukraine's ports and food storage facilities, killing and injuring several civilians. US and Ukrainian officials have said that missile and drone strikes on the southern city of Odesa alone destroyed agriculture infrastructure and 60,000 tons of grain.

On Thursday, Moscow's defense ministry declared that "all vessels sailing in the waters of the Black Sea to Ukrainian ports will be regarded as potential carriers of military cargo," a warning that has sent wheat prices rising.

"Accordingly, the countries of such vessels will be considered to be involved in the Ukrainian conflict on the side Kyiv, the defense ministry said in a Wednesday statement. It added that several pockets of international water are "declared temporarily dangerous for navigation," and vessels have been warned that there are no longer safety guarantees.

A White House official confirmed the threat, and said the Biden administration has information that Russia may expand its assault on Ukraine's grain facilities to include attacks on commercial vessels. They added that Moscow even published a video claiming to have detected and detonated an alleged Ukrainian sea mine.

"Our information indicates that Russia laid additional sea mines in the approaches to Ukrainian ports. We believe that this is a coordinated effort to justify any attacks against civilian ships in the Black Sea and lay blame on Ukraine for these attacks," National Security Council Spokesperson Adam Hodge said in a statement shared with Insider.

Ukraine, however, went on to issue its own measures in response to Moscow's initial escalation. Kyiv's defense ministry said that beginning on Friday, any vessels heading to ports in mainland Russia and in Russian-occupied regions of Ukraine — like in Crimea or along the Sea of Azov — may likewise be viewed as transporters of military cargo.

This new exchange of threats over the Black Sea has raised the risk that conflict could erupt around what has long been a crucial trade route for Ukraine to be able to provide its bounty of wheat, commercial food and fertilizer to the world. The July 2022 grain deal originally saw Russia lift its military blockade of Ukrainian ports, allowing critical exports through humanitarian corridors.

"I deeply regret Russia's decision to terminate the implementation of the Black Sea Initiative, which has been a lifeline for global food security in a troubled world," UN Secretary-General António Guterres said this week. "Hundreds of millions facing hunger & consumers confronting a global cost-of-living crisis will pay the price."

It was not immediately clear as of Thursday evening local time if any commercial ships had been targeted, and publicly available data showed dozens of cargo and container vessels operating around the Black Sea. Both Russia and Ukraine technically possess the capability to deal a heavy blow to civilian ships, though through different capabilities — Moscow with its Black Sea Fleet and Kyiv with marine drones. Each side could also use anti-ship missiles.

"I think it ought to be quite clear to everyone in the world right now that Russia is using food as a weapon of war — not just against the Ukrainian people, but against all the people in the world, especially the most underdeveloped countries who depend on grain from the region," US State Department Spokesperson Matthew Miller told reporters at a Wednesday briefing when asked about Russia's threat to target commercial ships.

The militarization of the Black Sea is not the first time that strategic bodies of water have been threatened by a nearby conflict. During the Iran-Iraq War of the 1980s, conflict between the two sides spilled into the Persian Gulf and the adjacent Strait of Hormuz, with both militaries attacking merchant vessels traveling around the region's various ports.

Known as the Tanker War, this multi-year conflict saw scores of attacks against ships that were registered with dozens of different countries. These vessels included oil tankers, cargo ships, supply vessels, and even tug boats, according to the US Naval Institute. Hundreds of people were killed or wounded by the engagements, which involved missiles, rockets, grenades, gunfire, and mines.

The US even became directly involved in the conflict at one point. Kuwait in 1986 had asked for international assistance to help protect its tankers, and the Soviet Union agreed to do the job. Washington didn't want Moscow to have an edge, but domestic law prevented it from helping foreign ships. To skirt this, the US re-flagged several Kuwaiti vessels so they had American registry, thus awarding them US Navy protection.

Washington's involvement in the conflict eventually led to several deadly incidents, including an Iraqi missile strike on an American frigate, which killed dozens of sailors, and and a deadly skirmish between the US and Iran.