The three countries announced in February that they would donate 100 of the German-made tanks in the "coming months".

"The first 10 tanks have been sent to Ukraine. And more are on the way," the Danish armed forces said in a statement.

"A further 10 tanks have been delivered from the factory."

Danish troops in Germany are training Ukrainian forces to use the vehicles, the army added.

"I have no doubt that it will help them win the defence battle they are fighting right now," Army commander Gunner Arpe Nielsen said in the statement.

Denmark's Leopard 1 A5 tanks were operational in its defence until 2005. In 1997, the country purchased 51 Leopard 2A4 tanks and the older Leopard 1 A5 models were phased out.