Local authorities in Russia claimed on Friday that Ukrainian helicopters hit an oil refinery close to the border.
A fire broke out due to an explosion at the facility after the strike, said a statement by Vyacheslav Gladkov, governor of the western Belgorod region.
The helicopters entered the region's airspace and struck the refinery at a low altitude some 40 kilometers (25 miles) from the border, Gladkov said, adding that nobody had been killed or injured in the attack.
Almost 200 firefighters have been deployed to help contain the blaze, according to Russian news agency TASS.
'Eight fuel tanks are currently on fire. A foam attack is underway. A firefighting train has engaged. Some 194 people and 59 units of equipment are operating at the site of the fire,' the agency reported, citing the country's Ministry of Emergency Situations.
The Russian war against Ukraine, which started on Feb. 24, has been met with international outrage, with the EU, US, and Britain, among others, implementing tough financial sanctions on Moscow.
At least 1,232 civilians have been killed in Ukraine and 1,935 injured, according to UN estimates, with the true figure feared to be far higher.
More than 4 million Ukrainians have also fled to other countries, with millions more internally displaced, according to the UN refugee agency.
Reporting by Emre Gurkan Abay in Moscow
Writing by Handan Kazanci
Anadolu Agency
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