MOSCOW/KYIV (Reuters) -Russia said Ukrainian artillery hit a Russian town for a third time this week and drones struck two oil refineries in an uptick in attacks on Russian territory as Ukraine prepares a Western-backed push to end Moscow's invasion.
Inside Ukraine, Russian-installed officials said five people had been killed in Ukrainian army shelling of a Russian-occupied village in the east, where Russia has fought months of bloody and inconclusive battles to try to seize more territory.
There was no immediate comment from Ukraine on the Russian reports, in a week when the two countries accused each other of spreading terror in their capitals with air strikes.
Thousands of civilians have been killed in Ukraine and towns and cities laid to waste since Moscow's forces invaded 15 months ago, but Tuesday marked only the second time Moscow had come under direct fire - from a flurry of drones - although oil and military facilities elsewhere in Russia have been hit.
In the Russian town of Shebekino on the Ukrainian border, two of four wounded people were hospitalised and shells damaged an apartment building, four homes and a school as well as power lines, Belgorod governor Vyacheslav Gladkov said.
Later, Gladkov told Russian television there had been more Ukrainian shelling of Shebekino and a fire had broken out at an industrial site.
Both sides say they are targeting the buildup of each other's forces and military equipment ahead of a Ukrainian counteroffensive, which it says will come in days or weeks, to try to drive Russian forces out of eastern and southern regions.
Away from the front lines of the conflict, the United Nations was trying to salvage a deal allowing safe Black Sea grain exports.
To that end, the U.N. has made a "mutually beneficial" proposal that Ukraine, Russia and Turkey begin preparatory work for the transit of Russian ammonia through Ukraine, a source close to the talks said on Wednesday.
Ukrainian President Volodymyr Zelenskiy, in his nightly video address, accused Russia of blocking all activity at the port of Pivdennyi, with 1.5 million tonnes of agricultural products unable to move.
"... the blockade of one port in Ukraine poses extremely serious risks for different nations, particularly those with relations that Russia tries to use for speculative purposes."
The U.N. and Turkey brokered the Black Sea Grain Initiative between Moscow and Kyiv last July to help tackle a global food crisis aggravated by Russia's invasion of Ukraine, a leading grain exporter.
ARTILLERY FIRE INTENSIFIES IN BAKHMUT
Russian-installed officials in Ukraine's eastern Luhansk region - one of four Moscow claims to have annexed - said Ukraine had killed five people and wounded 19 in a rocket attack on a farm in the village of Karpaty.
In the fiercely contested eastern Ukrainian city of Bakhmut, Russia was replacing Wagner private army troops with regular forces - paratroops and motorised rifle units - but intensifying its artillery shelling, Ukrainian military officials said on Wednesday night.
"The days to come will show whether the rotation strengthens or weakens them," Serhiy Cherevatyi, spokesperson for Ukraine's eastern grouping of troops, told Ukrainian television.
Russia's defence ministry said it had pushed Ukrainian forces back around two settlements in Donetsk province, part of a 1,000-km (620-mile) front line that has barely moved despite months of fighting that has cost tens of thousands of lives.
Reuters was not able to verify either side's reports.
Drones attacked two oil refineries 40-50 miles (65-80 km) east of Russia's biggest oil export terminals on Wednesday, according to Russian officials, who did not attribute blame. They said a fire at one of the terminals was later put out.
Ukrainian drones struck wealthy districts of Moscow on Tuesday and two people were injured, according to the Russian capital's mayor. The Kremlin said Moscow's air defences worked effectively but had room for improvement.
Russia's ambassador to Washington accused it of encouraging Ukraine to attack. The White House said it does not know who carried out the Moscow drone strikes but reiterated that the U.S. does not support attacks inside Russia.
The United States, Britain and Germany are among Western nations to have supplied arms to Ukraine on condition it uses them to defend itself and retake Ukrainian territory occupied by Russia, which they say launched an unprovoked war of conquest.
The White House on Wednesday announced the latest in a series of U.S. aid packages for Ukraine that includes up to $300 million worth of air defence systems and ammunition.
Russia says it is waging a "special military operation" to neutralise a threat from Kyiv's moves towards the West.
(Reporting by Guy Faulconbridge, Pavel Polityuk, Tom Balmforth, Max Hunder, Olena Harmash, Valentyn Ogirenko, Gleb Garanich and Ron Popeski; writing by Philippa Fletcher, Mark Heinrich and Grant McCool; Editing by Sharon Singleton, William Maclean and Diane Craft)