By Pavel Polityuk
KYIV (Reuters) - Shelling hit a high-voltage power line on Friday at a major Ukrainian nuclear power station captured by Russia, prompting the plant's operators to disconnect a reactor despite no radioactive leak being detected.
Ukraine's state nuclear power company Energoatom blamed Russia for the damage at the Zaporizhzhia power station, Europe's largest. Earlier this week, the United Nations nuclear watchdog appealed for access to the plant, which Washington says Russia is using as a battlefield shield.
Russia's defence ministry accused Ukrainian forces of shelling the plant, which was captured by Russian forces in early March in the opening stage of the war, saying a leak of radiation had been avoided only by luck.
It said that as a result, the generating capacity of one unit had been reduced and power supply to another had been cut. In addition, the nearby city of Enerhodar had power and water supplies problems, a ministry statement said.
It was not the first time that military action has caused alarm at Zaporizhzhia, where the U.N.'s International Atomic Energy Agency had at times reported losing connection with surveillance systems that keep track of nuclear material.
The Russian-installed administration of Enerhodar said in a statement fire had broken out and that power necessary for the safe functioning of reactors had been cut off. The plant continues to be run by its Ukrainian technicians.
Energoatom said the plant, about 200 km (160 miles) northwest of the Russian-held port of Mariupol in southeast Ukraine, was still operational and no radioactive discharges had been detected.
A decision had been taken to disconnect one reactor from the network because of damage to a 330 kilowatt high-voltage power distribution line linking the plant to the thermal power station, it said.
Further east, both sides claimed small advances while Russian artillery bombarded towns and villages across a wide area in a now-familiar tactic.
U.S. WEAPONS PACKAGE
The next weapons package to Ukraine from the United States was expected to be $1 billion, one of the largest so far, three sources briefed on the matter told Reuters.
If signed in its current form, it will include munitions for long-range weapons and armoured medical transport vehicles, the sources said.
The package is expected to be announced as early as Monday and would add to about $8.8 billion in aid the United States has given Ukraine since Russia's invasion on Feb. 24.
In other developments, three grain ships left Ukrainian ports on Friday and the first inbound cargo vessel since the Russian invasion was due in Ukraine to load, marking further steps in the Kyiv government's efforts to resuscitate its economy after five months of war.
Russian President Vladimir Putin meanwhile was meeting Turkish President Tayyip Erdogan, who is cultivating a role as a mediator in the war, in the Russian city of Sochi.
"The international community cannot end the war in Ukraine by ignoring Russia," said Fahrettin Altun, a top aide to Erdogan.
Turkey helped negotiate the agreement that on Monday saw the first grain ship leave a Ukrainian port for foreign markets since the invasion.
On Friday, two grain ships set off from Chornomorsk and one from Odesa carrying a total of about 58,000 tonnes of corn, the Turkish defence ministry said.
The Turkish bulk carrier Osprey S, flying the flagof Liberia, was expected to arrive in Chornomorsk on Friday to load up with grain, the Odesa regional administration said.
Russia and Ukraine normally produce about one third of the world's wheat, and the United Nations had warned that the halt in grain shipments through the Russian-dominated Black Sea could lead to famine in other countries, particularly in Africa, Asia and the Middle East.
"We expect that the security guarantees of our partners from the U.N. and Turkey will continue to work, and food exports from our ports will become stable and predictable for all market participants," Ukrainian Infrastructure Minister Oleksandr Kubrakov said.
Ukraine's Seaport Authority said on Monday 68 ships were berthed in Ukrainian ports with 1.2 million tonnes of cargo on board, two thirds of it food.
BATTLE FOR STRONGHOLD
Since Russia invaded Ukraine in what Putin termed a "special military operation", the conflict has settled into a war of attrition fought largely in the east and south of Ukraine.
Moscow is trying to gain control of the largely Russian-speaking Donbas, comprised of Luhansk and Donetsk provinces, where pro-Moscow separatists seized territory after the Kremlin annexed Crimea to the south in 2014.
Russia's TASS news agency on Friday cited separatist forces as saying they and Russian troops had taken full control of Pisky in Donetsk region, a fortified village held by Ukrainian troops and close to Donetsk city, which is in the hands of Russian-backed separatist forces.
But Ukrainian presidential adviser Oleksiy Arestovych said: "There is very little evidence of any movement here. They (the Russians) made an attempt to advance but it was unsuccessful."
Ukraine has turned the village into a stronghold, seeing it as a buffer against Russian-backed forces holding Donetsk city about 10 km to the southeast.
TASS also said fighting was taking place in the city of Bakhmut, north of Donetsk and Russia's next main target.
Arestovych said Ukrainian forces had recaptured two villages near Izyum in Kharkiv region, which borders Russia, and were advancing on a third.
Reuters could not verify either side's assertions about battlefield developments.
(Reporting by Reuters bureaux; Writing by Nick Macfie, Angus MacSwan and Daphne Psaledakis; Editing by Mark Heinrich and Grant McCool)