ANKARA - Tens of thousands of demonstrators took to the streets of Turkey’s capital Ankara Saturday in protest against Prime Minister Recep Tayyip Erdogan’s government, which has been rocked by a vast corruption probe.As Erdogan arrived home after a week-long tour to Asia, about 20,000 protesters gathered at Ankara’s major Sihhiye Square, chanting “revolution will clean this filth” and “they are thieves”.Some protesters were also handing out fake dollars with Erdogan’s photo on them.The corruption scandal implicating close allies of Erdogan has rattled his government to its core, and poses the biggest challenge to his 11-year rule.It erupted on December 17, when several public figures, including high-profile businessmen and the sons of three ministers, were detained over allegations of bribery for construction projects as well as illicit money transfers to sanctions-hit Iran.Forced into a major cabinet reshuffle after the three concerned ministers resigned, the firebrand prime minister has responded angrily to the probe, calling it a “dirty plot” to discredit his government. He sacked hundreds of police chiefs in a major purge and has moved to curb the powers of the judiciary. Erdogan’s government, in power since 2002, has accused loyalists of US-exiled cleric Fethullah Gulen, whose movement wields influence in the police and judiciary, of instigating the corruption probe.Lami Ozgen, one of the protest leaders, said the scandal shed light on the true face of both the government and the Gulen movement. “The crisis has made it known to the public how those who abuse religion and faith... are fond of wealth, luxury and splendour, how they worship money and how they see bribery as their direction to Mecca,” Ozgen said.Gulen was a major supporter of Erdogan’s ruling AKP party when it first came to power in 2002. But the two have parted ways after the government moved to shut down a network of private schools run by the movement.“We will not be a mere spectator to this power struggle, because they are ... eating up our salaries and the future of our children,” said Ozgen.Gulen, who left Turkey for the United States in 1999 after being accused of plotting to form an Islamic state, has denied involvement in the graft investigation.The government has vowed to press ahead with a contentious reform package which would give the justice ministry more powers to decide the composition of the Supreme Board of Judges and Prosecutors - the country’s top judicial body - and strip it of the power to pass decrees. “It is out of the question for us to withdraw the proposal,” local media quoted Justice Minister Bekir Bozdag as saying.The parliament began on Friday to debate the AKP-proposed changes which have been slapped down by the judicial body itself as unconstitutional and sparked criticism from the United States and the European Union. Erdogan has lashed out at a “judicial coup”, accusing prosecutors running the case of plotting to undermine him and his government.The escalating tensions have also revealed a heated competition between Erdogan and his former ally President Abdullah Gul ahead of presidential elections in August. Gul, who is expected either to be re-elected or be the next prime minister should Erdogan become president, has so far adopted a conciliatory approach toward the crisis and commentators say he will be in a dilemma if the controversial bill comes his way.“While on the one hand Gul wants to separate himself from the wrongdoings of Erdogan’s AKP, on the other he will need both Erdogan’s approval and the AKP’s support for his political hopes. This is his dilemma,” analyst Ihsan Yilmaz wrote in Today’s Zaman, a newspaper affiliated with the Gulen movement. “This is a very formidable challenge and dilemma that requires him to show leadership skills, prudently taking a serious risk,” he commented.