KIEV — Petro Poroshenko was sworn in as president of Ukraine on Saturday and issued a plaintive call for separatists fighting government forces to lay down their arms and negotiate an end to the conflict that is convulsing the country.
The billionaire chocolate manufacturer began his inaugural address with a peace overture to residents of the restive east, at one point switching out of the Ukrainian language in which he delivered the bulk of his speech to speak in Russian.
‘‘I don’t want war. I don’t want revenge,’’ he said, adding that he would not negotiate with ‘‘gunmen and other scoundrels’’ but would offer amnesty to those who ‘‘do not have the blood of peaceful citizens on their hands.’’
He also offered safe passage out of Ukraine for Russian nationals who have crossed the border from Russia to join, and in some cases lead, separatist units.
Poroshenko said Ukraine must seek to mend its tattered relations with Russia, but he made clear that he would not even consider giving up its claim to Crimea.
The peninsula, where a majority of residents are ethnic Russians, voted overwhelmingly in March to secede from Ukraine and become part of Russia.
‘‘Crimea was, is, and will be Ukrainian soil,’’ Poroshenko said to a standing ovation from everyone except the Communist Party faction in Parliament, adding that ‘‘all other things can be discussed.’’
But he also dedicated a part of his remarks to the need to restore trust in government and kick-start the economy.
He said he was prepared to sign an agreement with the European Union that would grant Ukrainian citizens the right to travel visa-free throughout Europe and said he considered such a move a precursor to seeking full membership in the European Union.
‘‘We are turning back to Europe,’’ he said. ‘‘This path is irreversible.’’
Poroshenko also appealed to Ukrainians to root out corruption from public life.
‘‘We need an anticorruption pact between the government and the people,’’ he said. ‘‘Bureaucrats do not take bribes, and people do not give bribes. We will not be able to change the country unless we change ourselves.’’
He referred to corruption in the armed forces, as well, saying he aimed to rebuild the depleted military into an elite fighting force.
‘‘The word general must become identified not with the word corruption, but with the word hero,’’ he said.
Ukrainians, he added, ‘‘will not drown in an ocean of corruption and disorder.’’
Poroshenko called for new parliamentary elections to produce a body that better reflects current political sentiment. Elections were last held in 2012.
‘‘Let’s face it,’’ he said. ‘‘The current composition of this distinguished assembly does not match the mood of society.’’
The 48-year-old Poroshenko, who has promised to sell off most of his vast business empire and focus on governing, was elected two weeks ago.
He is expected to juggle a number of urgent issues that have plunged Ukraine into crisis — ending the fighting that has uprooted thousands of frightened civilians, bringing transparency and honesty to government and getting the faltering economy moving.
His inauguration is being greeted with great optimism, at least in the central and western part of this country of 45 million people, far from the combat zones in the east.
The very existence of a unified Ukraine is at stake. Six months of upheaval have ratcheted up tensions between Russia and the West to Cold War heights, and Poroshenko’s inauguration offers a glimmer of hope to those seeking to avoid a full-blown civil war that could break the country apart.
In a brief moment that underscored the buoyant hopes many have, a member of the honor guard accidentally dropped his rifle as Poroshenko walked past on a red carpet. The commentator on state television characterized the fallen rifle as a good omen, symbolizing a laying down of arms.
In an initial indication that Poroshenko’s presidency could lead to an easing of tensions, Russia’s ambassador to Ukraine, Mikhail Zurabov, told the Ukrainian Interfax news agency that Russia is willing to negotiate with Poroshenko.
Zurabov said the new leader ‘‘bears no responsibility for the tragedy in the east, including the military tragedy.
It gives the opportunity for Russia to view him as a partner for negotiations.’’