"We again call for an urgent international investigation into the poisoning of Mr Navalny and full transparency and cooperation with the OPCW," Borrell said following the Foreign Affairs Council’s meeting.
He added that the bloc would hold a "comprehensive discussion" on Russia next month.
Navalny fell ill during a domestic flight in Russia on August 20. He was initially treated in the Siberian city of Omsk, where the plane had to urgently land.
Two days later, once the doctors established he was fit for cross-border aerial transportation, the 44-year-old was flown to Charite for further treatment.
Moscow has demanded Germany to provide evidence.
On September 7, Navalny awakened from a medically-induced coma and separated from ventilators in the Berlin-based Charite clinic. The first internet appearance he since made was a picture of himself and family from the hospital ward posted earlier this week on the first day that he breathed on his own.