“Any attempts at changing this situation” are “immediately and demonstratively punished,” Kasko told reporters.
Kasko was seen as one of the main crusaders in an uphill campaign to clean up one of Ukraine’s most powerful agencies.
US Ambassador Geoffrey Pyatt tweeted that Kasko’s resignation represented “a blow to Ukraine’s reform progress.”
“Kasko was a champion for change w/in (within) the Prosecutor General’s Office,” Pyatt wrote.
The latest strike against Ukraine’s reformist credentials came 12 days after Economy Minister Aivaras Abromavicius also quit the government over similar charges.
Abromavicius accused a top Poroshenko ally of trying to position his own people in the economy ministry in order to win control over the cash flows of the nation’s vast but opaque defence and energy industries.
The Lithuanian-born economy chief was one of several foreign experts tasked by Poroshenko in December 2014 to revive the war-ravaged country’s economy and set the country on a path to sustainable and transparent growth.
Abromavicius’s resignation and Poroshenko’s inability to persuade him to change his mind sparked instant concern among both Kiev’s Western allies and the International Monetary Fund — the global lender spearheading Ukraine’s economic rescue plan.
IMF chief Christine Lagarde bluntly noted that Ukraine now “risks a return to the pattern of failed economic policies that has plagued its recent history.”
And US Vice President Joe Biden spoke to Poroshenko twice last week about Ukraine’s need deliver on its promise to clean up the bureaucracy and graft that had become endemic since the country’s independence from the Soviet Union in 1991.
Shokhin has been a lightning rod of criticism for months because of his alleged attempts to cover up financial crimes committed by his staff.
But he is seen as a close Poroshenko ally and has thus far survived waves of political attacks that have come since his February 2015 appointment.