An anti-corruption agency established in Ukraine two years ago was expected to be the driving force that would uproot the endemic graft that depleted the nation's resources and worried its Western allies.But the National Anti-Corruption Bureau of Ukraine instead has come under fire from allies of President Petro Poroshenko who are trying to curtail its operations and authority.NABU chief Artem Sytnik told The Associated Press in a weekend interview that fear is behind the recent attempts by political and business elites to weaken the agency that was supposed to be a visible symbol of reform in Ukraine.'The old and new elites are quite scared' after realizing 'there are no untouchables anymore,' Sytnik said.Last month, the Security Service of Ukraine and the prosecutor general's office derailed a sting operation by undercover NABU agents to catch a State Migration Service official suspected of issuing passports and residence permits for bribes. The agencies accused NABU of illegal eavesdropping and released the names of its agents, blowing their covers.Poroshenko's faction and its allies in parliament also have submitted a bill that would allow lawmakers to fire the anti-corruption agency's director with a simple majority vote. Under current law, NABU's chief can only be fired for a criminal conviction, a provision that was intended to ensure independence.'Those attacks are directly linked to the fact that we investigate an increasing number of criminal cases involving people who are in control of the media, material or administrative resources, which they turn against us,' Sytnik said.Since its creation in 2015, NABU has investigated 461 cases involving business executives, government officials and judges accused of involvement in corrupt schemes.Sytnik thinks the current campaign against his agency results from a probe that targeted the son of Interior Minister Arsen Avakov for alleged involvement in a scheme to embezzle 14 million hryvnias (about $520,000) allocated for purchasing police rucksacks.Avakov has insisted his son was innocent and alleged that NABU of falling under political influence.International Monetary Fund Managing Director Christine Lagarde expressed concern about the recent developments 'that could roll back progress that has been made in setting up independent institutions to tackle high-level corruption, including the National Anti-Corruption Bureau.'Fighting corruption is a key demand of the Ukrainian society, is crucial to achieving stronger and equitable growth, and is part of the government's commitment under the program with the IMF,' Lagarde said in a statement last week.She urged the Ukrainian government and parliament to safeguard NABU's independence and to move quickly to set up an independent anti-corruption court 'to credibly adjudicate high-level corruption cases.'IMF made the establishment of a court where corruption cases could be prosecuted a condition for releasing further installments of a $17.5-billion aid package as Ukraine grapples with the separatist conflict in the east.In what was seen as another attempt to block anti-corruption efforts, lawmakers from Poroshenko's faction and their allies voted Thursday to dismiss the chairman of the anti-corruption committee in parliament.'The former and present corrupt elite have colluded,' the ousted committee head, Yegor Sobolev, said. 'Their plan is to break the independence of anti-corruption bodies, replace them with fake ones and stop the process of cleaning the government,' he added.Popular anger over corruption was a factor in months of protests that drove Ukraine's former Russia-leaning president from office in February 2014. Poroshenko's failure to oversee progress has caused growing impatience and triggered calls for his impeachment led by Mikheil Saakashvili, the former Georgia president turned Ukrainian opposition leader.After leading several rallies in Kiev, Saakashvili was arrested Friday on allegations that he colluded with Ukrainian businessmen tied to Russia to topple the president. Saakashvili scoffed at the charges, alleging they resulted from longtime hostility between him and Russian President Vladimir Putin.'The detention of Saakashvili shows how far Poroshenko is ready to go to muzzle his opponents and those who expose corruption,' Sobolev said.Thousands of Saakashvili's supporters marched across the Ukrainian capital Sunday, demanding his release and calling for Poroshenko to be impeached.'Poroshenko is continuing the worst traditions of the old nomenklatura,' said Vitaly Shabunin, the head of watchdog group the Center for Fighting Corruption. 'The same old elites, the same people have taken different political slogans, but their way of thinking and their goals have remained the same.