Germany’s foreign minister is visiting Kyiv in the latest public display of support for Ukraine by its Western partners.

Annalena Baerbock renewed Berlin’s calls for partners to send more air defence systems, as Russia pounds Ukraine with missiles, glide bombs and rockets. Germany is the second-biggest supplier of military aid to Ukraine after the United States.

But deliveries of promised weapons and ammunition from Nato countries like Germany have been slow and have left Ukraine vulnerable to a recent Russian push along parts of the front line.

Ukraine’s depleted troops are trying to hold off a fierce Russian offensive along the eastern border in one of the most critical phases of the war, which is stretching into its third year.

Germany recently pledged a third US-made Patriot battery for Ukraine, but Kyiv officials say they are still facing an alarming shortfall of air defences against the Russian onslaught.

The Kremlin’s forces have used their advantage in the skies to debilitate Ukraine’s power grid, hoping to sap Ukrainian morale and disrupt its defence industry.

Ms Baerbock, accompanied by Ukrainian energy minister Herman Halushchenko, toured a thermal power plant in central Ukraine that was heavily damaged on April 11. In the plant’s scorched interior, workers of Centrenergo, a state company that operates the plant, were still scooping up rubble several weeks after it was hit.

Ukrainian President Volodymyr Zelensky said the Kremlin’s forces are still focusing their efforts on the eastern Donetsk province and north-eastern Kharkiv region, where explosive-laden Russian glide bombs are wreaking destruction on military and civilian areas.

“This brings us back again and again to the need for air defence — for additional defence systems that could significantly mitigate the difficulties for our warriors and the threat to our cities and communities,” Mr Zelensky said late on Monday on social media.

Mr Zelensky claimed Ukraine’s forces are still in control of the contested areas, though Russia says it has captured a series of border villages.

It was not possible to independently verify either side’s battlefield claims.

Ms Baerbock had planned to visit Kharkiv on Tuesday but the trip had to be called off for security reasons, German news agency dpa reported. Almost 11,000 people have been evacuated from Kharkiv border areas since Russia launched its offensive actions there on May 10.

A Russian overnight drone attack hit transport infrastructure in Kharkiv city, the regional capital, damaging more than 25 trucks, buses, and other vehicles, regional governor Oleh Syniehubov said. Seven people were injured, he said.

Ukraine’s general staff said the frequency of Russian attacks in Kharkiv slowed on Monday, though fighting continued.

Russian troops are also conducting reconnaissance and sabotage raids in Ukraine’s northern Sumy and Chernihiv regions, shelling border settlements and laying more minefields, according to Dmytro Lykhovii, Ukraine’s general staff spokesman. The front line is some 620 miles long.

Ms Baerbock was due to meet with Ukrainian foreign minister Dmytro Kuleba in Kyiv. German Chancellor Olaf Scholz has been resisting appeals from Ukrainian officials to provide Taurus missiles, which are equipped with stealth technology and have a range of up to 300 miles.

The German and Swedish-made missiles would be able to reach targets deep in Russia from Ukrainian soil. But Berlin has balked at that prospect, saying that sending the missiles would bring a risk of it becoming directly involved in the war.

The restriction on not allowing Ukraine to fire at Russia has denied Kyiv the ability to strike at Russian troops and equipment massing for attacks on the other side of the border, a Washington-based think tank said.

“These US and Western policies are severely compromising Ukraine’s ability to defend itself against current Russian offensive operations in northern Kharkiv (region) or any area along the international border where Russian forces may choose to conduct offensive operations in the future,” the Institute for the Study of War said in an assessment late on Monday.

Ms Baerbock said in a statement that Ukraine’s prospective membership of the European Union is “the necessary geopolitical consequence of Russia’s illegal war of aggression”.

Ukraine has made “impressive progress” and must not let up in reforms to the judicial system, in fighting corruption and on media freedom, she said.

Germany will host a reconstruction conference for Ukraine next month. Rebuilding the country is predicted to cost hundreds of billions of dollars.