Long sort-after by Kyiv, Challenger and Leopard tanks were received just in time for a spring offensive planned by the Ukrainian army.

Whether or not to supply Ukraine with heavy battle tanks was subject to a long debate, with some countries fearing it would escalate the conflict with Russia.

Britain was the first major ally to agree, with Germany eventually giving in.

The announcement comes after a Euronews investigation debunked false claims circulating on social media that Leopard 2 tanks were getting stuck in the mud.

In a Facebook post, Ukrainian Defense Minister Olesksiy Reznikov announced "British Challengers, American Strykers and Cougars and German Marders" have been "added to the Ukrainian units".

He posted an accompanying photo with the vehicles, without specifying the day they arrived.

Moscow has previously vowed to annihilate all western-made tanks shipped to Ukraine, with a Russian company offering a bounty of $72,000 to the first soldiers who destroy or capture one.

On Monday, German Chancellor Olaf Scholz announced Berlin had supplied "very modern" Leopard battle tanks.

Later, his Ministry of Defense said 18 tanks had been delivered.

"Our tanks arrived as promised and punctually in the hands of our Ukrainian friends," Defense Minister Boris Pistorius said in a statement.

"I'm sure they can make a difference on the pitch."