* Khodorkovsky meets family a day after whirlwind release
* Oil tycoon fell out with Putin before his arrest
* Khodorkovsky travelled to Germany after release
By Michelle Martin and Lidia Kelly
BERLIN/MOSCOW, Dec 21 (Reuters) - Former oil tycoon Mikhail Khodorkovsky was reunited with family members in Berlin on Saturday, a day after he was released from a decade-long jail term during which he became one of Russian President Vladimir Putin's most prominent critics.
Khodorkovsky, 50, was released from a remote prison near the Arctic Circle on Friday after Putin pardoned him with the stroke of a pen. He immediately flew to Berlin, where he was joined by his relatives, including his elderly parents, Marina and Boris, on Saturday.
"My family is finally reunited and we're very, very happy to be together after the 10 years of separation," his son Pavel Khodorkovsky, who arrived from the United States, said outside the Adlon Hotel in the German capital.
"As you can imagine my father is going through a lot right now," he said.
Khodorkovsky, who had been in jail since his arrest in October 2003 on fraud and tax evasion charges, was convicted twice of financial crimes, to which he pleaded not guilty.
In an excerpt from the first on-camera comment to the media since his release, Khodorkovsky told Russian magazine The New Times in an interview that his family was allowed only a handful of overnight visits during the years he was in prison.
"There was an opportunity - three days, once per quarter, during four years out of the 10 - to spend nights in the visiting room," said Khodorkovsky, who looked composed and relaxed in a black turtleneck sweater.
Kremlin critics say Khodorkovsky angered Putin by funding opposition parties, questioning state decisions on oil pipeline policy, raising corruption allegations and fashioning himself as an enlightened, Western-style post-Soviet executive.
Supporters say the former Yukos oil company chief was jailed to curb political challenges to Putin, bring his oil assets under state control and warn other tycoons to toe the line.
Yukos was bankrupted and sold off. Its main production asset now forms the core of state oil company Rosneft, which is headed by an influential Putin ally, Igor Sechin.
Putin's decision to pardon Khodorkovsky, who had been due to be released next August, was widely seen as an effort to improve Russia's image before it hosts the Winter Olympics in February in the Black Sea resort city of Sochi.
The pardon sent Russian share prices upward briefly but economists said real reforms to Russia's economy and its justice system would be needed to remove the discount its stocks sell at compared to other emerging markets.
Putin said on Thursday that Khodorkovsky sought a pardon because his mother was ill, and his spokesman said the request meant Khodorkovsky had admitted guilt. Khodorkovsky said in a statement on Friday that although he had asked Putin for a pardon for unspecified family reasons, he did not admit guilt.
Russian media have speculated that fears of new charges that could have threatened to keep him in jail past next August could have influenced his decision to seek a pardon.
Putin's spokesman has said Khodorkovsky is free to return to Russia.
The United States and European Union welcomed Khodorkovsky's release but made clear they want to see Russia make sustained efforts to strengthen rule of law and respect for human rights.
"Putin is making efforts to revamp the battered façade of his authoritarian Russia," said German opposition Greens' politician Marieluise Beck, who met Khodorkovsky on Saturday.
His release "cannot blind us to the fact that Russia is just as far away from being a state governed by the rule of law as it was before this pardon," she said in a statement.