KYIV, Dec. 13 – Recent attacks on the National Anti-Corruption Bureau of Ukraine are caused by the fact that the agency had come close to exposing senior officials, NABU chief Artem Sytnik said.

"The old and new elites are quite scared" after realizing "there are no untouchables anymore," NABU chief Artem Sytnik said in an interview with The Associated Press.

But the NABU instead has recently come under fire from allies of President Petro Poroshenko who are trying to curtail its operations and authority.

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. (ap/ez)