Poroshenko Takes Ukraine Helm With Tough Words for Russia

He also expressed new resolve, saying Ukraine would never accept Russia’s annexation of Crimea, a point he also made in a face-to-face meeting with President Vladimir V. Putin of Russia on Friday.

In a forceful inaugural address, Mr. Poroshenko, 48, called on rebel fighters in eastern Ukraine to put down their weapons and promised safe passage for “Russian mercenaries” who wished to return home. But he said there would be no negotiations with armed insurgents, raising the prospect of further bloodshed as the Ukrainian military seeks to quash the rebellion.

Though the United States and its Western allies expressed new hope of a diplomatic resolution after meetings with Mr. Putin in France at a commemoration of the 70th anniversary of D-Day, Russia’s intentions in Ukraine remain unclear, and there have been mixed signals on whether there is consensus among Western nations over further sanctions if diplomatic efforts fail.

Mr. Poroshenko, after being installed in a mostly solemn ceremony at the Ukrainian Parliament, said he hoped to mend relations with Russia. “Citizens of Ukraine will never enjoy the beauty of peace unless we settle down our relations with Russia,” he said.

At the same time, however, he voiced no willingness to tolerate recent Russian aggression or the annexation of Crimea, which Mr. Putin has described as the righting of a historical accident that separated the peninsula from its Russian roots.

 “Russia occupied Crimea, which was, is and will be Ukrainian soil,” Mr. Poroshenko told an audience that included Vice President Joseph R. Biden Jr. and other international dignitaries. “Yesterday, in the course of the meeting in Normandy, I told this to President Putin: Crimea is Ukraine soil. Period. There can be no compromise on the issues of Crimea, European choice and state structure.”

Mr. Poroshenko also said he would move swiftly to sign political and economic agreements with the European Union that Ukraine’s former government, under heavy Russian pressure, backed away from in November, setting off the civil unrest. “My pen is in my hands,” he said, adding later, “European democracy, for me, is the best form of government invented by mankind.”

In a sign of outreach, Russia returned its ambassador, Mikhail Y. Zurabov, to Kiev to attend the inaugural festivities. Mr. Zurabov had been recalled to Russia after the ouster of the former Ukrainian president, Viktor F. Yanukovych.

And a day after President Obama demanded that Russia stop the flow of weapons and fighters into Ukraine, Russian news agencies reported that Mr. Putin had ordered tighter controls on the border to prevent people from crossing illegally.

Still, violence continued to flare in eastern Ukraine. An assassination attempt on Denis Pushilin, a pro-Russian, separatist leader in Donetsk, on Saturday resulted in the shooting death of an assistant, Maksym Petruhin. Photographs on Ukrainian news sites showed Mr. Petruhin, wearing a business suit, lying face down on a street alongside a parked car with at least seven bullet holes in the rear door panel.

Mr. Poroshenko won the presidency in a landslide on May 25, in a special election that was called after months of civil unrest toppled Mr. Yanukovych, who fled to Russia.

For many years, Mr. Poroshenko served in Parliament, including a stint as speaker. He was foreign minister under President Viktor A. Yushchenko and trade and economics minister under Mr. Yanukovych.

He earned his fortune making chocolate, and Russia is a major market for his company, Roshen, which has factories and other facilities there. His deep business ties in Russia and his long experience in Ukrainian politics had led to hope that he could negotiate successfully with the Kremlin.

In his inaugural speech, however, he was resolute against Russian intervention. “The issue of territorial integrity of Ukraine is not subject to discussion,” he said. “I have just sworn ‘with all my deeds to protect the sovereignty and independence of Ukraine,’ and I will always be faithful to this sacred promise.”

The ceremony was imbued with ritual. Mr. Poroshenko swore the oath of office with his hand on the 16th-century Peresopnytsia Gospel. He was presented with a bejeweled presidential necklace, which framed his tie of sky blue and yellow, Ukraine’s national colors. He was also given the bulava, a scepter that is a historical symbol of power.

Mr. Poroshenko opened his speech by recognizing the so-called Heavenly Hundred demonstrators who were killed in clashes with the police in Kiev in the days before Mr. Yanukovych was forced from power.

 “Many people thought that we got independence without any difficulty,” he said. “It is not true.”

After calling for a moment of silence, he turned his attention to the pro-Russian violence in the east and switched from speaking Ukrainian to Russian.

He promised amnesty for fighters who put down their weapons and safe passage for Russian insurgents who wanted to go home. To the peaceful citizens of eastern Ukraine, he said he would welcome dialogue.

He offered conciliatory actions, promising to go to eastern Ukraine “with peace, with a project of government decentralization, with a guarantee of free usage of Russian language in your region, with the strong intention not to divide people into right and wrong Ukrainians, with respect for the specifics of regions, for the right of local communities to their peculiarities in the issues of historic memory, pantheon of heroes, religious traditions.”

Mr. Poroshenko also promised to pursue a jobs program and to fight the corruption that has plagued Ukraine throughout its post-Soviet history. He said he would push for parliamentary elections later this year, aiming to meet a demand of demonstrators — many of whom are still camping out in Independence Square in the center of Kiev — who say that changing presidents is not sufficient.

He also acknowledged that the uprising had deeply altered the country. “The victorious revolution of dignity not only changed the government,” he said. “The country has changed. People have changed.”

In conjunction with Mr. Biden’s visit, the White House announced $48 million in new aid to Ukraine, as well as $8 million for Moldova and $5 million for Georgia. Moldova and Georgia are also expected to sign agreements with the European Union this month and have come under Russian pressure as a result.

Meeting with Mr. Poroshenko, Mr. Biden saluted his efforts to combat corruption. “Corruption is a cancer,” he said. “It eats away the fabric of democracy.”

He also reiterated American support for Ukraine.

 “America’s with you,” Mr. Biden said. “That is not hyperbole.”