Ukraine and Russia: What you need to know right now

Ukrainian forces struggled to hold their ground in bloody street-to-street fighting in the eastern frontline city of Sievierodonetsk as President Zelenskiy said the situation was difficult, also pledging to retake Russia's gains.

Ukrainian forces struggled to hold their ground in bloody street-to-street fighting in the eastern frontline city of Sievierodonetsk as President Zelenskiy said the situation was difficult, also pledging to retake Russia's gains. FIGHTING

* The governor of the Luhansk region, Serhiy Gaidai, said the defenders were finding it hard to repel Russian attacks in the center of Sievierodonetsk. * Sievierodonetsk, Lysychansk, and Popasna remain the most difficult places, Zelenskiy said late on Tuesday.

* Moscow said its troops have been advancing. Zelenskiy said the "heroic defense" of Donbas was ongoing. Reuters could not independently verify the situation on the ground. * More than 1,000 Ukrainian soldiers who surrendered in the city of Mariupol have been transferred to Russia for investigation, Tass news agency reported, citing a Russian law enforcement source.

* Russia has handed over the bodies of 210 Ukrainian fighters, most of whom who died defending the city of Mariupol from Russian forces at a vast steel works, the Ukrainian military said. * Zelenskiy said Ukraine would launch next week a "Book of Executioners" to detail war crimes. Russia denies targeting civilians in the conflict.

ECONOMY * Russian shelling destroyed the warehouses of one of Ukraine's largest agricultural commodity terminals in the Black Sea port of Mykolaiv last weekend, the head of the region said. His account could not be independently verified.

* Ukraine could export a maximum of only 2 million tonnes of grains a month if Russia refuses to lift its blockade of the country's Black Sea ports, Ukraine's first deputy minister for Agrarian Policy and Food said. * The Russian and Turkish defense ministers discussed a potential grain export corridor from Ukraine and northern Syria, Turkey's defense ministry said.

* The World Bank board approved $1.49 billion of additional financing for Ukraine to help pay wages for government and social workers, expanding the bank's total pledged support to over $4 billion. * Under heavy pressure from Western sanctions and airspace bans, Russian state airline Aeroflot said it planned to raise up to 185.2 billion roubles ($3 billion) in an emergency share issue.

NUCLEAR * Radiation detectors in the Exclusion Zone around Ukraine's defunct Chornobyl nuclear power plant are back on line for the first time since Russia seized the area on Feb. 24, and radiation levels are normal, the U.N. nuclear watchdog said.