* IAEA says Zaporizhzhia plan still producing electricity
* Zelenskiy: Russia plans 'decisive energy blow on all Europeans'
* Russia delays pipeline reopening in blow to Europe
* G7 finance chiefs agree on Russian oil price cap
KYIV, Sept 4
A nuclear power plant on the front line of the Ukraine war again lost external power, U.N. inspectors said on Saturday, fuelling fears of disaster while Moscow kept its main gas pipeline to Germany shut to hurt economies of Kyiv's friends in the West.
The Zaporizhzhia plant, Europe's largest, had its last remaining main external power line cut off, although a reserve line continued supplying electricity to the grid, the International Atomic Energy Agency (IAEA) said.
Only one of the station's six reactors remained in operation, the agency said in a statement.
The plant, seized by Russian troops shortly after their Feb. 24 invasion, has become a focal point of the conflict, with each side blaming the other for nearby shelling.
A standoff over Russian gas and oil exports ramped up last week as Moscow vowed to keep its main gas pipeline to Germany shuttered and G7 countries announced a planned price cap on Russian oil exports.
The energy fight is a fallout from President Vladimir Putin's six-month invasion of Ukraine, underscoring the deep rift between Moscow and Western nations as Europe steels itself for the cold months ahead.
"Russia is preparing a decisive energy blow on all Europeans for this winter," Ukrainian President Volodymyr Zelenskiy said in his nightly address on Saturday, citing the Nord Stream 1 pipeline's continued closure.
Zelenskiy has blamed Russian shelling for an Aug. 25 cutoff, the first Zaporizhzhia was severed from the national grid, which narrowly avoided a radiation leak. That shutdown prompted power cuts across Ukraine, although emergency generators kicked in for vital cooling processes.
Moscow has cited Western sanctions and technical issues for energy disruptions, while European countries have accused Russia of weaponising supplies as part of its military invasion.
NUCLEAR CONCERNS
Kyiv and Moscow have traded accusations about attacks on the Zaporizhzhia plant, which is still operated by Ukrainian staff.
An IAEA mission toured the plant on Thursday and some experts have remained there pending the release of a report by the United Nations nuclear watchdog in coming days.
The remaining inspectors noted one reactor was still producing electricity "for cooling and other essential safety functions at the site and for households, factories and others through the grid," the IAEA said on Saturday.
The plant said in a statement the fifth reactor was switched off "as a result of constant shelling by Russian occupation forces" and that there was "insufficient capacity from the last reserve line to operate two reactors."
Deteriorating conditions amid the shelling have prompted fears of a radiation disaster that the International Red Cross has said would cause a major humanitarian crisis.
Ukraine and the West accuse Russia of storing heavy weapons at the site to discourage Ukraine from firing on it. Russia, which denies the presence of any such weapons there, has resisted international calls to relocate troops and demilitarise the area.
Russia's defence ministry on Saturday accused Ukrainian forces of mounting a failed attempt to capture the plant. Reuters could not verify the report.
Turkey on Saturday also offered to facilitate the situation.
GAS AND OIL
Announcing that it would not make a planned restart of gas shipments through the Nord Stream 1 pipeline, one of Russia's main supply lines to Europe, state-controlled energy giant Gazprom GAZP.MM blamed a technical fault.
Gazprom said on Saturday that Germany's Siemens Energy ENR1n.DE was ready to help repair broken equipment but that there was nowhere available to carry out the work. Siemens said it has not been commissioned to carry out maintenance work for the pipeline but it is available.
The indefinite delay to restarting Nord Stream 1, which runs under the Baltic Sea to supply Germany and others, deepens Europe's problems securing fuel for winter as energy prices lead a surge in living costs.
Finance ministers from the Group of Seven wealthy democracies - Britain, Canada, France, Germany, Italy, Japan and the United States - said on Friday the cap on the price of Russian oil aimed to reduce "Russia's ability to fund its war of aggression whilst limiting the impact of Russia's war on global energy prices".
The Kremlin said it would stop selling oil to any countries that implemented the cap.
Russia calls its invasion of its neighbour "a special military operation." Kyiv and the West say it is an unprovoked aggressive war against a former part of the Soviet Union.
The United States and other countries have pledged fresh military aid for Kyiv to fight against an invasion that had killed thousands of people and displaced millions.
Ukraine launched a counteroffensive last week targeting the south, particularly the Kherson region, occupied by Russians early in the conflict.
