Russia's defence ministry said on Thursday it had taken out military infrastructure at Ukraine's air bases and "suppressed" its air defences, Russian news agencies reported.
The ministry denied reports that its aircraft had been downed over Ukraine.
Earlier, Ukraine's military had said five Russian planes and one helicopter were shot down over its Luhansk region.
"The air defence assets of the Ukrainian armed forces have been suppressed," Interfax news agency quoted the ministry as saying.
"The military infrastructure of the Ukrainian Armed Forces' air bases has been taken out of action.
"Information in foreign media about a Russian plane allegedly being shot down is not true."


Britain pushes allies to boost Ukraine support as Zelenskyy lands in London
Erdogan says US, others must press Israel to abide by Gaza ceasefire
EU vows financial backing for Kyiv
Tourists gawk and recoil at Trump's destruction of the White House East Wing
