(AFP) - Germany faced a strong backlash from allies on Saturday over its refusal to supply Ukraine with its vaunted Leopard tanks to bolster its fighting capacity in the nearly year-long war with Russia.

On Friday, some 50 nations agreed to provide Kyiv with billions of dollars' worth of military hardware, including armoured vehicles and munitions needed to push back Russian forces.

But German Defence Minister Boris Pistorius told reporters on the sidelines of the event at the US Ramstein Air Base that despite heightened expectations, "We still cannot say when a decision will be taken, and what the decision will be, when it comes to the Leopard tank."

Ukraine on Saturday denounced the "global indecision" of its allies on providing heavy-duty modern tanks, saying "today's indecision is killing more of our people."

"Every day of delay is the death of Ukrainians. Think faster," presidential adviser Mykhailo Podolyak tweeted.

Several allies echoed Ukrainian President Volodymyr Zelensky in saying the tanks were essential to Ukraine's fight with its much larger neighbour.

In a joint statement -- and a rare public criticism of Europe's top power -- the foreign ministers of the three Baltic states said they "call on Germany to provide Leopard tanks to Ukraine now."

"This is needed to stop Russian aggression, help Ukraine and restore peace in Europe quickly. Germany as the leading European power has special responsibility in this regard," said the statement, tweeted by Latvian Foreign Minister Edgars Rinkevics.

Berlin has been hesitant to send the Leopards or allow other nations to transfer them to Kyiv, with reports earlier in the week saying it would agree to do so only if the US provided its tanks as well. Washington has said providing its Abrams tanks to Ukraine is not feasible, citing difficulties in training and maintenance.

But expectations had grown ahead of Friday's Ukraine Contact Group meeting of around 50 US-led countries that Germany would at least agree to let other countries operating Leopards transfer them to Kyiv's army.

US Senator Lindsey Graham, a Republican from South Carolina who is currently visiting Kyiv, called on both sides to supply the machines.

"To the Germans: Send tanks to Ukraine because they need them. It is in your own national interest that (Russian President Vladimir) Putin loses in Ukraine."

"To the (US President Joe) Biden Administration: Send American tanks so that others will follow our lead," he said.

The pleas came as the Russian army said its troops had launched an offensive in Ukraine's Zaporizhzhia region, where fighting intensified this week after several months of an almost frozen front.

In its daily report Saturday, Moscow's forces said they carried out "offensive operations" in the region and claimed to have "taken more advantageous lines and positions".

- Funeral -

In Kyiv on Saturday, Zelensky attended the funeral of his interior minister and other officials who were killed in a helicopter crash outside the capital Wednesday.

Denys Monastyrsky, one of Zelensky's top aides, became the highest-ranking Ukrainian official to die in the war that Russia launched on February 24, 2022.

The cause of the crash that killed him and 13 others when the chopper fell near a kindergarten was still under investigation.

US officials said Ukraine still faced an uphill battle against Russian forces who still occupy one-fifth of the country 11 months after invading.

But they spoke of a possible campaign in the coming weeks by Ukraine to retake parts of its territory.

US Joint Chiefs Chairman General Mark Milley pointed to the substantial amount of equipment -- much of it armoured vehicles and artillery -- that Ukraine was being pledged at Ramstein, as well as the large-scale training of its forces by allies.

"I do think it's very possible for the Ukrainians to run a significant tactical or even operational-level offensive operation to liberate as much Ukrainian territory as possible," Milley said.

But the Kremlin warned Friday that Western tanks would make little difference on the battlefield.

"One should not exaggerate the importance of such supplies in terms of the ability to change something," Kremlin spokesman Dmitry Peskov told reporters.

© Agence France-Presse