Russia has reportedly returned to using Iranian suicide attack drones provided by Iran, the Ministry of Defence (MOD) has said.
It is the first time in three weeks there have been reports of attacks from the Iranian-provided drones, the MOD said in an intelligence update posted on Twitter.
"These events remain to be verified, but it is likely that Russia exhausted its previous stock of several hundred Shahed-131s and 136s and has now received a resupply," the MOD said.
"On 06 December 2022, the Ukrainian General Staff reported shooting down 17 Unmanned Aerial Vehicles (UAVs), including 14 Shahed-136s.
"On 07 December 2022, Ukrainian officials reported the use of Iranian-provided [One Way Attack] UAVs targeting Zaporizhzhia and Dnipro oblasts."
The MOD said the last reported shooting down of Shahed-136s in Ukraine was on 17 November.
"If verified, it is likely that Russia has recommenced attacks with newly delivered [One Way Attack] UAV systems."
Iran has denied it is supplying UAVs to Moscow, but Tehran's track record would indicate otherwise and the US State Department says the Iranians are also training Russian drone pilots.
Both Russia and Ukraine have been using UAVs during the war.
Drone expert David Hambling told Forces News in October that the conflict in Ukraine "is far and away the largest scale use" of drones ever seen in warfare.
"The genie is well and truly out of the bottle now and you do feel the world is suddenly waking up to the fact that if your military hasn't got lots of drones, they're going to be at a massive disadvantage against anyone who does," he said.