German Chancellor Olaf Scholz unveiled 650 million euros ($685 million) of new military aid as he came to Kyiv on Monday, vowing Berlin would remain Ukraine's biggest backer in Europe at a crucial moment in the war, with Donald Trump set to return to the White House, Reuters reported.

The visit, his first to Kyiv since the early months of Russia's invasion in 2022, comes weeks after his governing coalition collapsed, setting him up for a tough election battle in February.

The political turmoil in Europe's biggest economy adds to a growing feeling of uncertainty in Ukraine, with Russian troops advancing ever faster. It is unclear how much Kyiv's European allies can step up support for Ukraine if Trump cuts back help from its biggest backer.

Scholz and President Volodymyr Zelenskiy met at an undisclosed location and reviewed military drones manufactured by Ukrainian and German firms.

Scholz was expected to hold talks later with Zelenskiy, whose government is urging NATO to invite Ukraine to join the military alliance at a meeting in Brussels this week.

While trumpeting Germany as Ukraine's second-biggest weapons supplier after the United States, Scholz has repeatedly refused to send Taurus cruise missiles to Ukraine, fearing this could draw his country into a direct conflict with Russia.

He also drew fire from allies, including Zelenskiy himself, for holding a phone call with Russian President Vladimir Putin in November, for the first time in almost two years, which critics saw as a bid for domestic political gain.

"Germany will remain Ukraine's strongest supporter in Europe," Scholz wrote on X, adding that he would promise Zelenskiy "further military equipment worth 650 million euros", to be delivered this month.

Ukraine an issue in German election campaign

Backing for Ukraine is shaping up as a major issue in Germany's election.

Friedrich Merz, the conservative opposition leader who is on course to unseat Scholz, has said Germany should send Taurus missiles and at the weekend said Scholz was raising unnecessary fears.

Roderich Kiesewetter from the conservative Christian Democrats (CDU) accused Scholz of "campaigning on the backs of the Ukrainian population and at the same time ... feeding the Russian fear narrative".

"He is increasingly isolating Germany and endangering our security," he told Monday's Augsburger Allgemeine newspaper.