The speaker of the Ukrainian parliament was elected prime minister on Thursday in what could mark an end to a months-long government crisis in a country crippled by a separatist war in the east.

In recent months, political tensions have risen and some respected reformers have resigned, citing disenchantment with the government's cronyism and entrenched corruption.

The Supreme Rada on Thursday voted 250-57 for Volodymyr Groysman, who was nominated by President Petro Poroshenko.

The outgoing prime minister, Arseniy Yatsenyuk, resigned earlier this week after weeks of pressure for him to step down. Yatsenyuk's cabinet survived a no-confidence vote in February, but two parties left the governing coalition to protest the failure to oust the prime minister, who was under fire over the worsening economy and slow pace of reforms.

Yatsenyuk became prime minister after Ukraine's former Russia-friendly president was chased from power in February 2014 following massive pro-European protests. Poroshenko was elected several months later with broad support and a seal of approval from Western leaders.

Groysman has been perceived as a conciliatory figure after the governing coalition refused to back U.S.-born Finance Minister Natalie Jaresko, who has been lauded as a West-friendly reformist untainted by cronyism and corruption.

In his acceptance speech, Groysman said Ukraine faces three major challenges: corruption, poor governance and populism that he described as "a no less threat than the enemy in the east."

Fighting between Russia-backed separatists and government troops which engulfed swathes of eastern Ukraine in April 2014 has claimed more than 9,100, and a political settlement remains a dim prospect.

While presenting Groysman's nomination at the parliament Poroshenko mentioned that he originally wanted a "technocrat government" in an apparent reference to Jaresko but the governing coalition opposed. Jaresko helped to negotiate a deal to restructure Ukraine's $15 billion debt and has been negotiating a bail-out with the International Monetary Fund. Many of Ukraine's backers in the West have said Jaresko's appointment would signal Kiev's commitment to much-needed structural reforms that could help Ukrainian oligarchs.

Groysman's acceptance speech was often greeted by shouts and murmur of discontent.

Oleh Lyashko, leader of the right-wing Radical Party which exited the coalition earlier this year, dismissed the vote as an oligarchs' coup to secure their vested interests.

Yulia Tymoshenko, a former prime minister and a leading figure behind Ukraine's 2005 revolution, announced after the vote that her party will oppose the new government.

After a crushing defeat in the 2014 presidential vote, Tymoshenko largely disappeared from public view before being elected into parliament later that year. The latest opinion polls show Tymoshenko as the nation's second-favorite politician, gaining ground on Poroshenko.

Ukrainian reformers fear that Groysman's appointment will give the oligarchs a free hand in running the entire economy without government supervision. Others, however, welcomed the new government as a chance to bring a painful political crisis to a close.

"The new prime minister and the cabinet help to bring the government out of a months-long lethargy which is fraught with an even deeper crisis and early elections," Kiev-based analysts Vadim Karasyov said.

In Germany, Foreign Minister Frank-Walter Steinmeier lauded Groysman's appointment as a "chance to end the phase of political uncertainty in Kiev" and urged to speed up the pace of reform, saying that Ukraine "has no time to lose."