Berlin, the second-biggest supplier of military assistance to Kyiv after the United States, is seeking to offer the reassurances after the shift in focus to the Middle East war prompted concerns about waning support for Ukraine.

It was Pistorius's second visit to Kyiv since he became defence minister at the start of this year, and it comes a day after US Defence Secretary Lloyd Austin also made an unannounced trip to Ukraine to offer Washington's continued support.

"I am here again, firstly to pledge further support, but also to express our solidarity and deep bond and also our admiration for the courageous, brave and costly fight that is being waged here," Pistorius said laying flowers at Maidan square in central Kyiv.

Pistorius arrived by train and was due to hold talks with his Ukrainian counterpart as well as President Volodymyr Zelensky.

The visit comes after an increase in Russian air attacks on Ukraine and as Kyiv braces for an expected rise in strikes on the country's energy facilities over the coming winter months.

As well as the wreath-laying ceremony at Kyiv's Maidan square -- where thousands joined for protracted pro-democracy protests a decade ago -- Pistorius was due to visit a military training centre.

After some initial hesitation, Germany drastically ramped up its support for Ukraine in the wake of Russia's invasion and has delivered a huge array of armaments to Kyiv, ranging from heavy battle tanks to air defence systems and ammunition.

The conflict has also spurred the government to embark on an overhaul of the country's creaking military, with Chancellor Olaf Scholz unveiling a 100-billion-euro ($109-billion) fund to boost the armed forces.

Haunted by guilt over its role in World War II, successive governments had considered the armed forces a low priority, and it suffered from years of neglect.

Since the outbreak of the Israel-Hamas war, Germany has offered strong support to Israel in its fight against the Palestinian militants.

But Scholz pledged last month Germany would still maintain its aid to Kyiv, insisting that "we will support Ukraine as long as necessary".