Moscow, Sep 10 (IANS): US Secretary of State Mike Pompeo has said that there is a "substantial chance" that the suspected poisoning of Russian opposition figure Alexei Navalny was ordered by senior officials in Moscow, the media reported on Thursday.

Pompeo made the remarks in an interview on Wednesday when asked if there would be any ramifications for the Russian government over apparent attacks on its political opponents, the BBC reported.

In response, he said the US, along with the European Union (EU), had made clear to Russia "our expectations that they will hold those responsible for this accountable. We'll do our best to come to a conclusion about who was responsible too".

"I think people all around the world will see this kind of activity for what it is.

"And when they see the effort to poison a dissident, they recognise that there is a substantial chance that this actually came from Russia," the BBC quoted Pompeo as saying in the interview.

Pompeo however, declined to say how the US would respond, but said Washington would play its part to "reduce the risk that things like this happen again".

Meanwhile, President Donald Trump has given no indication of how the US will respond to the poisoning,adding that "we haven't had any proof yet but I will take a look".

On Wednesday, Russia's Foreign Ministry summoned the German Ambassador to Moscow, Geza Andreas von Geyr against the "unfounded accusations and ultimatum" over the case.

On Tuesday, G7 Foreign Ministers and the High Representative of the European Union issued a statement demanding Russia to "urgently and fully establish transparency on who is responsible for this abhorrent poisoning attack", Xinhua news agency reported.

Navalny, the 44-year-old staunch critic of Putin, fell ill on a flight from the Russian city of Tomsk to Moscow on August 20 and the plane had to make an emergency landing in the city of Omsk.

He reportedly went into coma after being hospitalized in Omsk and was later transferred to Germany for treatment.

On Monday, the Charite hospital in Berlin, where Navalny is being treated, issued a statement saying that his condition had improved and he was being weaned off mechanical ventilation after coming round from his coma.