ANKARA/KYIV--Russia has said it would resume its participation in a deal freeing up grain exports from Ukraine, reversing a decision that world leaders warned would increase hunger globally.

Russia, whose forces invaded Ukraine on Feb. 24, announced the reversal on Wednesday after Turkey and the United Nations helped keep Ukrainian grain flowing for several days without a Russian role in inspections.

The defence ministry justified the resumption by saying it had received guarantees from Ukraine that it would not use the Black Sea grain corridor for military operations against Russia.

"The Russian Federation considers that the guarantees received at the moment appear sufficient, and resumes the implementation of the agreement," the ministry said in a statement.

Ukrainian President Volodymyr Zelenskiy said it was important to stand up to "crazy Russian aggression that destabilises international trade".

"After eight months of Russia's so-called special operation, the Kremlin is demanding security guarantees from Ukraine," Zelenskiy said in his nightly video address.

"This is truly a remarkable statement. It shows just what a failure the Russian aggression has been and just how strong we all are when we maintain our unity."

The grain deal, originally reached three months ago, had helped alleviate a global food crisis by lifting a de facto Russian blockade on Ukraine, one of the world's biggest grain suppliers. The prospect of it collapsing this week revived fears of a worsening food crisis and rising prices.

The prices of wheat, soybeans, corn and rapeseed fell sharply on global markets after Russia's announcement.

SHAKY

Andrey Sizov, head of the Russia-focused Sovecon agriculture consultancy, said Moscow's decision was "quite an unexpected turnaround" but the deal remained shaky given uncertainty about whether it would be extended past its Nov. 19 expiry.

A European diplomat briefed on the grain talks said Russian President Vladimir Putin was likely to use the need for an extension as a way to gain leverage and dominate a Nov. 13-16 G20 summit in Indonesia.

Zelenskiy credited Turkey and the United Nations for making it possible for ships to continue moving out of Ukrainian ports with cargoes after Russia suspended participation on Saturday.

In an interview with Turkish broadcaster ATV, Turkish President Tayyip Erdogan said he and Zelenskiy discussed sending grain to African countries. Putin had earlier proposed sending grain to countries such as Djibouti, Somalia and Sudan first, where it is badly needed.

The July 22 grains deal aimed to help avert famine in poor countries by injecting more wheat, sunflower oil and fertilizer into world markets.

Russia suspended its involvement in the deal saying it could not guarantee safety for civilian ships crossing the Black Sea after an attack on its fleet. Ukraine and Western countries called that a false pretext for "blackmail", using threats to the global food supply.

KHERSON COUNTER-OFFENSIVE

Ukrainian forces have recently wrested back territory in the east and south, and Russia has sought to slow their momentum with stepped up missile and drone strikes targeting the energy grid.

On Wednesday, authorities in the region of the capital, Kyiv, began emergency shutdowns of the power-generating system after a spike in consumption, the regional administration said.

The shutdowns were necessary to "avoid major accidents with power equipment", authorities said in a statement, after Russian attacks badly damaged the grid.

Russia has said it targeted infrastructure as part of what it calls its "special military operation" to degrade the Ukrainian military and remove what it says is a potential threat against Russia's security.

As a result, Ukrainian civilians have endured power cuts and reduced water supplies in recent weeks. Russia denies targeting civilians, though the conflict has killed thousands, displaced millions and left some Ukrainian cities in ruins.

In the southern Kherson region, where Ukrainian forces are proceeding slowly with a counter-offensive against Russian occupying forces, Russian-installed authorities were proceeding with a drive to persuade residents to evacuate, the Ukrainian military said.

Residents who had collaborated with occupying forces were leaving and some departing medical staff had taken equipment from hospitals, it said.

Residents of the town of Nova Zburivka had been given three days to leave and were told that evacuation would be obligatory from Nov. 5.

Russian authorities have repeatedly said that Ukraine could be preparing to attack the massive Kakhovka dam and flood the region. Kyiv denies that.

"Obviously, we are afraid of this. That is why we are leaving," resident Pavel Ryazskiy, who was evacuated to Crimea, said of the possibility the dam could be destroyed.

Reuters was not able to verify the battlefield reports.

In Washington on Wednesday the United States said it had information that indicated North Korea is covertly supplying Russia with a "significant" number of artillery shells for the war.

White House national security spokesperson John Kirby did not provide evidence but he told a briefing that North Korea was attempting to obscure the shipments by funnelling them through the Middle East and North Africa.