Deputy Prime Minister Vladimir Groisman became Ukraine's new acting prime minister, media reported Friday.
Reports cited the website of Ukraine's government and the Facebook page of Interior Minister Arsen Avakov, but neither had confirmed the appointment as of Friday afternoon.
Prime Minister Arseniy Yatsenyuk announced his resignation Thursday, citing disagreements with the parliament over the budget, energy sector and army financing.
Groisman, 36, oversaw regional development, construction and utilities in Yatsenyuk's government, which was formed in February.
He previously headed the city of Vinnitsa, the home turf of confectionery maker Roshen, which is the linchpin of President Petro Poroshenko's business empire.
Groisman also heads the commission investigating the crash of Malaysia Airlines flight MH17, which killed 298 last week.
The crash happened in an area controlled by pro-Russian separatists in eastern Ukraine, and official Kiev says either the insurgents or their alleged backers in Moscow shot down the plane with a missile.
Yatsenyuk stepped down after the disintegration of the ruling coalition in Ukraine's parliament, the Verkhovna Rada, which will mean parliamentary elections in the near future.
The snap vote was endorsed by Poroshenko, who expressed hope it would purge the Rada of supporters of his predecessor Viktor Yanukovych, ousted in February in a street revolution.