The results of tests Germany says prove Russian dissident Alexei Navalny was the victim of a nerve agent attack have been handed to the Organization for the Prohibition of Chemical Weapons.
The German government sees no reason to give the evidence directly to Russia, spokeswoman Martina Fietz told reporters on Wednesday.
"We continue to appeal to the Russian side to deliver information," Fietz added.
She described the poisoning of Navalny as a violation of international laws against chemical weapons, rather than a mere spat between Berlin and Moscow.
A spokesman for the German Defence Ministry confirmed the test samples had been handed to the OPCW, of which Russia is a member.
Navalny, 44, was taken to Berlin's Charite hospital two days after falling ill on a domestic Russian flight on August 20.
The facility said on Monday Navalny, one of President Vladimir Putin's most vocal critics, had been woken from his medically induced coma and was responding to verbal stimuli.
The Russian government denies involvement and has so far refused to conduct a criminal investigation into the claim Navalny was poisoned.
Germany's ambassador to Russia, Geza Andreas von Geyr, went to the Russian Foreign Ministry on Wednesday for talks on the dispute.
According to Russian Foreign Ministry spokesperson Maria Zakharova, Moscow was expecting Germany to present sufficient evidence to substantiate the claim Navalny was poisoned with the Soviet-developed nerve agent Novichok.
However the German Foreign Ministry in Berlin had said earlier the ambassador's appointment had been scheduled long in advance.
The Russian Foreign Ministry issued a statement saying Germany had been thwarting Russian doctors' attempts to establish dialogue with their German colleagues on assessing the matter.
"The unconstructive approach by the German authorities is accompanied by groundless accusations against Russia," the Russian Foreign Ministry said.
"The massive misinformation campaign that has been unleashed clearly demonstrates that the primary objective pursued by its masterminds is to mobilise support for sanctions, rather than to care for Alexei Navalny's health or establish the true reasons for his admission to hospital."
Meanwhile, US Secretary of State Mike Pompeo said the poisoning was likely ordered by "senior Russian officials".
"I'll say this much. I think people all around the world see this kind of activity for what it is. And when they see the effort to poison a dissident, and they recognise that there is a substantial chance that this actually came from senior Russian officials," he told the Ben Shapiro Show.
Pompeo added that Washington will "take a look" at what to do in response to the poisoning.