Germany's armed forces, the Bundeswehr, have also taken on the training of soldiers in a fast-track programme.

 According to Ukrainian information, a complete weapon system also arrived from the United States, and the Netherlands also supplied system components.

The mobile battery is one of the most advanced surface-to-air systems in the world. Patriot stands for "phased array tracking radar to intercept on target."

It can be used to combat enemy aircraft, ballistic missiles and cruise missiles.

With the system, the German government is making a contribution so that Ukraine can repel the numerous Russian attacks that also aim to destroy civilian infrastructure.

"I am glad that our Patriot fire unit in Ukraine is protecting the civilian population against the brutal Russian air attacks. Together with our allies, we are delivering what Ukraine needs most urgently - and repeatedly pushing our own performance limits to do so," German Defence Minister Boris Pistorius said on Wednesday.

The highly motivated Ukrainians had mastered the demanding training in the air force in minimal time, Pistorius said, adding: "Now they are returning to the battlefield and helping to make the skies over Ukraine belong to Ukrainians again."

"Today, our beautiful Ukrainian sky becomes more secure because Patriot air defence systems have arrived in Ukraine," Ukrainian Defence Minister Oleksii Reznikov tweeted.

"Our air defenders have mastered them as fast as they could.

And our partners have kept their word," the minister added.

"This is the result of hard work led by our president [Volodymyr Zelensky]," he added.

Ukrainian soldiers received training from Germany and the US at a site in a NATO member country, where joint drills were also held, sources close to the German military told dpa. The Ukrainian air defence personnel were given the finishing touches to be able to successfully use the Patriot to defend against Russian air attacks, which mainly target civilian infrastructure.

Individual training for Ukrainian soldiers has begun, explained Markus König, commander of Anti-Aircraft Missile Group 21 and the person responsible for training the Ukrainians.

"With the help of simulation-based training, the Ukrainian crews were gradually confronted with increasingly complex situations. Again and again they had to find their way in the most varied of threat scenarios, correctly assess the situation in order to ultimately make the right decision to successfully combat an air raid," the lieutenant colonel said.

Ukrainian operating crews are now able to set up the weapons system and fire on approaching targets. That will contribute to a significant strengthening of their air defence, the German officer said.

More than two weeks ago, Ukraine also received another Iris-T SLM air defence system from Germany - the second of these systems.

The delivery has taken place, a government spokeswoman told the German daily Süddeutsche Zeitung in remarks published on Wednesday.

According to the mayor of Kiev, Vitali Klitschko, the system developed by the Diehl armaments group and other partners has helped improve the defence of the greater Kiev area, the newspaper said.

According to Klitschko, the system hits its targets 100% of the time.