KIEV, Ukraine — Minutes after taking office on Monday, Ukraine’s new president, Volodymyr Zelensky, announced a snap parliamentary election that he hopes will consolidate his power and help him deliver on campaign promises to end endemic corruption and a prolonged separatist conflict.

Mr. Zelensky, a political neophyte who gained popularity as a television comedian, said in his inaugural address that his first priority is to reach a cease-fire in the war against Russian proxies in the country’s east that has claimed 13,000 lives.

The new president won a landslide victory in April, leading a political party, Servant of the People, that was registered just last year, and does not yet hold any seats in the Ukrainian Parliament. Voting for a new Parliament had been scheduled for October, but Mr. Zelensky dissolved the current Parliament and moved the election to July, aiming to seize an advantage while he remains very popular and his party is running far ahead of its rivals in most recent opinion polls.

During the campaign, he capitalized on the failure of the incumbent, Petro O. Poroshenko, a wealthy business magnate, to deliver economic growth, defeat corruption or end the war.