Ukrainian Prime Minister Arseniy Yatsenyuk said Sunday he had resigned.
"I have taken the decision to resign as prime minister of Ukraine. On Tuesday, April 12 my request will be submitted to the parliament," Yatsenyuk wrote on Twitter.
He said President Petro Poroschenko's political bloc would nominate current parliamentary speaker Volodymyr Groysman for the post of prime minister.
Yatsenyuk, who has held the office since February 2014, wrote that new government should be formed immediately in order to avoid "destabilization of [the] executive branch during a war."
Kiev was plunged in political uncertainty in February when the pro-Western coalition lost its legislative majority in parliament, prompting fears of further instability as Ukraine continues to grapple with the conflict with pro-Russian rebels in its eastern regions.