Navalny, a fierce, high-profile critic of Russian President Vladimir Putin, was flown to Germany last month after falling ill on August 20 on a domestic flight in Russia.
Alexei Navalny, a 44-year-old lawyer and anti-corruption campaigner who is one of Putin's fiercest opponents, is being treated at Berlin's Charite hospital after falling ill on a flight in Siberia.
Kremlin spokesman Dmitry Peskov saw no grounds for launching a criminal investigation into Navalny's condition, saying that it could have been triggered by a variety of causes.
"Navalny's condition is stable," said Jaka Bizilj, the head of the Cinema for Peace NGO after the flight touched down at Berlin's Tegel airport.
The Kremlin, an ally of the Stalinist regime, was not planning any talks at the highest level for the moment, he said.
Russian President Vladimir Putin thanked the German Chancellor Angela Merkel for visiting and said they would focus on 'the hottest' topics.
Russia's FSB said that two Russian citizens were arrested on Friday suspected of planning an attack in St Petersburg during the New Year festivities.
The Kremlin on Thursday rejected suggestions from a senior lawmaker that Russian women should not have sex with visiting World Cup fans, saying they would make up their own minds.
Jerusalem is one of the most thorny issues of the Israeli-Palestinian conflict, with both sides claiming it as their capital.
The Kremlin said on Thursday that a crisis communications link with the United States meant to avoid an accidental clash over Syria was being used by both sides.
In Washington, the State Department said there was no justification for the Russian move and that the United States "reserves the right to respond."
Vladimir Putin, who exit polls say won a fourth term as Russian president in Sunday's election, has tightened the Kremlin's grip on society since taking power 18 years ago.
Putin is predicted to win with around 70 percent of the vote despite a lacklustre campaign and his refusal to participate in televised debates.
Putin has always prided himself on respecting the constitution, which bars him from serving more than two presidential terms in a row.
The Kremlin said it had no information on a former Russian double agent who fell ill in Britain after exposure to an unknown substance, calling the incident 'tragic.'