German Foreign Minister Johann Wadephul made an unannounced visit to Kyiv on Monday, in a show of continuing support for Ukraine's fight to repel Russia's invasion as U.S.-led international peace efforts fail to make progress.

Wadephul was due to meet with Ukraine President Volodymyr Zelenskyy and Ukrainian Foreign Minister Andrii Sybiha.

Wadephul said in a statement that Germany will help Ukraine “continue to defend itself successfully — with modern air defense and other weapons, with humanitarian and economic aid."

Germany has been Ukraine's second-largest military backer after the United States, whose continuing support is in doubt.

However, Berlin has balked at granting Zelenskyy's request to provide Ukraine with powerful German- and Swedish-made Taurus long-range missiles. That is due to fears that such a move could enrage the Kremlin and end up drawing NATO into Europe's biggest conflict since World War II.

Instead, German Chancellor Friedrich Merz pledged in May to help Ukraine develop its own long-range missile systems that would be free of any Western-imposed limitations on their use and targets.

Wadephul was accompanied on his trip to Kyiv by German defense industry representatives.

Russia's invasion shows no sign of letting up. Its grinding war of attrition along the roughly 1,000-kilometer (620-mile) front line and long-range strikes on civilian areas of Ukraine have killed thousands of troops and civilians.

The Russian effort to capture more Ukrainian territory has been costly in terms of casualties and damaged armor. But Russian President Vladimir Putin has effectively rejected a ceasefire and hasn't budged from his war goals.

Putin “doesn't want negotiations, but (Ukrainian) capitulation," Wadephul said in his statement.

Russia launched its biggest combined aerial attack against Ukraine at the weekend, Ukrainian officials said, in its escalating bombing campaign that has further dashed hopes for a breakthrough in peace efforts.