MOSCOW -- Two prominent Russian opposition leaders were released from detention Thursday after spending 15 days in a Moscow jail for disobeying police.

Anti-corruption activist Alexei Navalny and left-wing politician Sergei Udaltsov were arrested on May 9 as they protested President Vladimir Putin's inauguration.

An unprecedented wave of anti-Kremlin protests has swept Russia's major cities, and Navalny and Udalstov are some of the movement's key leaders.

In what is seen as an attempt to crackdown on dissent, Russia's lower house of parliament on Tuesday gave preliminary approval to a bill increasing 200-fold fines for those taking part in unsanctioned protests. Opposition lawmakers have warned that the legislation would only fuel anger and destabilize Russia by robbing the public of a legal way to voice their grievances.

The Russian Duma is dominated by the Kremlin-backed United Russia party. United Russia's win in the December election marred by allegation of wide-spread vote-rigging was the initial trigger of street protests in Russia this winter.

About a hundred of Navalny supporters applauded and cheered him as he left the detention facility on the south-west outskirts of Moscow.

Navalny told the jubilant crowd that he would continue to fight against the regime even if that entails more jail time.

"They won't scare us with their iron beds and porridge," he said, referring to the conditions in jail. "I'm ready to enter this building two or twenty-two times if that's necessary."

Navalny said that the new legislation would backfire.

"The adoption of that bill would only increase the number of those attending sanctioned rallies and would make people taking part in illegal gathering resist even more fiercely."

Navalny, whose anti-corruption initiatives have thrived on generous public donations, voiced confidence that he and his supporters would have no difficulty raising the money however high new fines for protesters would be.

Also on HuffPost:



PUTIN WITH PUPPIES:
Loading Slideshow...
  • President Vladimir Putin pets his dog Conny before one of his meetings with officials in his office in the Novo-Ogaryovo residence outside Moscow on March 3, 2004. (Alexander Zemlanichenko, AFP / Getty Images)

  • Russian President Vladimir Putin plays with a dog in the village of Verkhniye Mondrogi August 18, 2001, during his summer vacations in Karelia. (Getty)

  • Russian President Vladimir Putin smiles as photographers try to make pictures of his dog Koney during his meeting with Jordan's King Abdullah II (not pictured) at Putin's residence in the Russian Black Sea resort of Sochi Aug.18, 2005. (Alexander Zemlianichenko, AFP / Getty Images)

  • Russian President Vladimir Putin hugs a Hungarian 'Puli' dog owned by Hungarian Prime Minister Ferenc Gyurcsany (R) and his wife Klara Dobrev on the balcony of the Prime Minister residence in Budapest, March 1, 2006. (Miklos Der, AFP / Getty Images)

  • Russian President Vladimir Putin pets his dog Kuni as Germany's Federal Chancellor Angela Merkel looks on as they address journalists after their working meeting at the Bocharov Ruchei residence in Sochi Jan. 21, 2007. (Axel Schmidt, AFP / Getty Images)

  • Russian President Vladimir Putin plays with a dog as former US President George Bush look at him at the Bush family house at Walker's Point in Kennebunkport, Maine in July 1, 2007. Putin arrived in the United States for a "lobster summit" with Bush, aimed at defusing tensions which have spiked over irritants such as missile defense. (Mikhail Klimentyev, AFP / Getty Images)

  • Russian President Dmitry Medvedev and Prime Minister Vladimir Putin, accompanied by a dog, play badminton at the presidential residence in Sochi on Aug. 14, 2009. (Dmitry Astakhov, AFP / Getty Images)

  • Russian President Dmitry Medvedev and Prime Minister Vladimir Putin, accompanied by a dog, drive in an electric buggy at the presidential residence in Sochi on August 14, 2009. (Dmitry Astakhov, AFP / Getty Images)

  • Russian Prime Minister Vladimir Putin hugs a Bulgarian shepherd dog, a present from his Bulgarian counterpart Boyko Borisov after their press conference in Sofia on Nov. 13, 2010. (Nikolay Doychinov, AFP / Getty Images)

  • Russian Prime Minister Vladimir Putin plays with his Bulgarian shepherd dog named Buffy during their meeting at Putin's residence outside Moscow, the Novo-Ogaryovo, on Dec. 9, 2010. (Alexey Druzhnin, AFP / Getty Images)

  • Russian Prime Minister Vladimir Putin greets a soldier's dog as he visits a division of the Ministry of Internal Affairs in Balashiha, outside Moscow on July 22, 2011. (Alexey Druzhnin, AFP / Getty Images)