Russian forces in Ukraine are using old armoured vehicles, packed with "several tonnes of explosives", as improvised explosive devices, the Ministry of Defence (MOD) has said.
In the latest defence update posted on Twitter, the MOD said there have been "several reports" of Russia using "vehicle-borne improvised explosive devices" (VBIED).
"The crew likely bail out of the vehicle after setting it on its course," the MOD said.
"Most Russian VBIED cases have been reported around Marinka, near Donetsk city, and started days after Chechen units reinforced the area: there is a realistic possibility that Chechen forces are pioneering the tactic.
"There is a heritage of Chechen fighters being skilled in IED use, dating back to the Chechen Wars from the 1990s.
"Chechens fighting for Ukraine were also reported to have made similar VBIEDs in January 2023."
The update continued: "Most of Russia's VBIEDs have almost certainly detonated before they reached their target through a combination of anti-tank mines and direct fire, bringing into question the viability of the capability.
"However, these VBIEDs cause extremely large explosions, which are still likely to have a psychological effect on defending forces."
The latest intelligence report comes as Ukrainian President Volodymyr Zelensky attended a Nato summit in Lithuania which featured talks on Kyiv joining the alliance.
Mr Zelensky voiced his frustration at Nato failing to produce a timeframe for Kyiv to become a member of the defensive alliance.
The war leader said on Tuesday that it was "absurd" for Nato to insist there are still military and democratic "conditions" for the eastern European country to meet before it can join once the conflict with Moscow is over.