Ukrainian media and a pro-Western lawmaker say Prosecutor-General Viktor Shokin resigned on February 16 after President Petro Poroshenko asked him and Prime Minister Arseniy Yatsenyuk to step down.
Shokin's deputy, meanwhile, said the prosecutor had taken a three-day vacation, but did not specify whether in fact he had resigned.
Shokin has faced accusations of stalling high-profile corruption cases against allies of Viktor Yanukovych, the former president who was toppled by protests in February 2014.
The Ukrainska Pravda newspaper cited an unidentified source in Shokin's office as saying that the prosecutor-general had tendered his resignation following a February 16 statement by Poroshenko that Shokin and Yatsenyuk should quit "in order to restore trust in the government."
The Ukrainian news portal lb.ua also cited an unidentified source as confirming Shokin's resignation.
Ukrainian lawmaker Mustafa Nayyem wrote on his Twitter feed that Shokin had resigned but did not indicate a source for this information, which could not be immediately confirmed.
Deputy Prosecutor-General Yuriy Sevruk was quoted later as saying that Shokin had taken a three-day vacation beginning February 15, and that he was serving as acting prosecutor-general in Shokin's absence.
"Viktor Nikolayevich [Shokin] appointed me on February 12 when he submitted [a notice] for a three-day vacation," the news portal UNN cited Sevruk as saying on February 16.
UNN also cited an unidentified source in the government’s personnel department as saying that, from a technical standpoint, Shokin could not have submitted a resignation letter on February 16 because he was on vacation.
U.S. officials, including the U.S. ambassador in Kyiv, have long made clear their position that Shokin should resign, and in Washington, Poroshenko’s call for Shokin to go was welcomed.
“The announcement to replace [Shokin] is a signal of Ukraine's seriousness about its reform process,” U.S. State Department spokesman Mark Toner told reporters on February 16.
"It's important to restore the confidence of the Ukrainian people in their justice system, but clearly there is an immense amount of work yet to be done in countering corruption, including in the prosecutorial service," Toner said.
Shokin was called out by name earlier this month by Economy Minister Aivaras Abromavicius, who announced his resignation and cited a "sharp escalation in efforts to block systemic and important reforms."
Vitaliy Kasko, another deputy prosecutor-general known for his pro-reform stance, resigned on February 15, telling journalists in Kyiv that "the straw that broke the camel's back" was a move by Shokin to take all of Kasko's activities under his control.
"The Prosecutor-General's Office today is a dead institution, in independence and efficiency, that nobody believes in anymore," he said.