But a Ukrainian commander says the highly mobile AMX-10 RC infantry fighting vehicles -- sometimes described as light tanks -- are "impractical" for front-line attacks, claiming one four-man crew has already died because of the vehicle's thin armour.

Kyiv said in April that the French vehicles -- designed for armed reconnaissance and attacks on enemy tanks -- were already in service.

But a 34-year-old battalion commander within the 37th Marine Brigade, who uses the call sign Spartanets, said the tanks' "thin armour" means they can be used as fire support, but not in front-line assaults.

"Unfortunately, there was one case when the crew died in the vehicle," the major told AFP on Friday.

"There was artillery shelling and a shell exploded near the vehicle, the fragments pierced the armour and the ammunition set detonated."

The crew of four inside were all killed, he said.

"The guns are good, the observation devices are very good. But unfortunately there is thin armour and it is impractical to use them in the front line (attack)," Spartanets said.

"There were such cases when a 152-mm shell exploded nearby and the shrapnel penetrated the vehicle," he said

He added that the French AMX-10 also had issues with gear boxes breaking down, possibly due to their use on dirt roads.

"Just sending out the (AMX-10) vehicles (into combat) so they get destroyed, I consider it is impractical and unnecessary because it's primarily a risk for the crew," Spartanets said.

He did not specify how many AMX-10s the elite combat formation has, and declined to show them to AFP reporters in the field.

Open-source intelligence website Oryx, which tallies equipment losses based on battlefield imagery, has counted three losses in Ukraine of AMX-10 RC light tanks.

Spartanets said his soldiers are gaining experience with the vehicles after undergoing a month's training in France, while adding this was not long enough to fully master its tactical use.

According to the French defence ministry, AMX-10s offer protection against light infantry fire.

Their combat weight is around 20 tonnes and they have wheels instead of tracks.

They were developed in the 1970s, and French armed forces have begun to replace them with more modern vehicles called Jaguar.

- 'Cool' Oshkosh -

The battalion commander compared the French-built vehicles unfavourably with MRAP-type armoured vehicles such as the American Oshkosh and British Husky, which he said could resist a direct strike by rocket-propelled grenades.

Washington in January also announced assistance to Ukraine including 55 MRAP (Mine-Resistant Ambush Protected) armoured vehicles.

Britain sent Husky support vehicles last year.

Spartanets showed AFP two Oshkosh camouflage-painted vehicles mounted on huge wheels.

One had some minor shrapnel damage to the hood, which he described as a "weak" point.

"Otherwise, in terms of protection, the vehicle is very cool," he said.

If one runs over a landmine, "a wheel flies off" but the vehicle remains intact, he said.

By contrast, when a Soviet infantry fighting vehicle (BMP or BMD) drives over a tank mine, "it is very sad for the crew and the vehicle", he added.

The recently formed 37th brigade has fighters positioned close to the Russian front line in the eastern Donetsk region.

The battalion commander said he took direct part in fighting around Blagodatne, a village recently retaken by Ukrainian forces.