Foreign ministers from the Group of Seven industrialized countries strongly criticized Tuesday what they have confirmed to be a poisoning attack on a Russian opposition leader and urged Moscow to be transparent in its investigation.

The ministers from the United States, Japan, Germany and elsewhere said in a statement that they are "united in condemning, in the strongest possible terms, the confirmed poisoning of Alexei Navalny."

Navalny, known as a prominent critic of Russian President Vladimir Putin, lost consciousness on a flight to Moscow after drinking tea at a Russian airport on Aug. 20. He was initially hospitalized in Russia, but later transferred to a hospital in Berlin as his wife sought treatment for him outside the country.

According to the G-7 statement, Germany has briefed the other countries on its clinical and toxicological findings, which conclude that Navalny was poisoned by a Russia-developed "Novichok" chemical nerve agent.

"Any use of chemical weapons, anywhere, anytime, by anybody, under any circumstances whatsoever, is unacceptable and contravenes the international norms prohibiting the use of such weapons," the ministers said, adding that they "call on Russia to urgently and fully establish transparency on who is responsible for this abhorrent poisoning attack."

Moscow has insisted that no toxic substances were found during checks at the Russian hospital where Navalny was first treated.

The Berlin hospital said Monday that the Russian opposition leader has come out of a coma. But he is still in intensive care and remains in serious condition, according to the G-7 statement.

The other G-7 members are Britain, Canada, France and Italy, plus the European Union.

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