Ukraine's new president Petro Poroshenko says his country will never give up Crimea and will not compromise on pursuing closer ties with Europe, sending a defiant message to Russia.

The 48-year-old billionaire took the oath of office before parliament, buoyed by Western support but facing an immediate crisis in relations with Russia as a separatist uprising continues in the east of his country.

Russia annexed the Crimean peninsula in March, weeks after street protests ousted Mr Poroshenko's pro-Moscow predecessor, in a move that provoked the deepest crisis in relations with the West since the Cold War.

"Citizens of Ukraine will never enjoy the beauty of peace unless we settle down our relations with Russia," Mr Poroshenko said in his inaugural speech that was greeted with a standing ovation.

"Russia occupied Crimea, which was, is, and will be Ukrainian soil."

He said he delivered this message to Russia's Vladimir Putin when the two met on Friday at a World War II anniversary ceremony in France.

Mr Poroshenko, who made his fortune as a confectionery maker and is known locally as the "Chocolate King", says he intends soon to sign the economic part of an association agreement with the European Union, as a first step towards full membership.

This idea is anathema to Moscow, which wants to keep Ukraine in its own post-Soviet sphere of influence.

His voice swelling with emotion, Mr Poroshenko stressed the need for a united Ukraine and the importance of ending the conflict that threatens to further split the country of 45 million people.

He said it would not become a looser federalised state, as advocated by Russia.

"There can be no trade-off about Crimea and about the European choice and about the governmental system," he said.

"All other things can be negotiated and discussed at the negotiation table.

"Any attempts at internal or external enslavement of Ukraine will meet with resolute resistance."

Cheering crowds later greeted him on a walkabout in blazing sunshine on the square in front of Kiev's St Sophia's Cathedral, decorated with the blue and yellow national flag.

Rebels urged to 'lay down the guns'

Since Mr Poroshenko's election, government forces have intensified their campaign against separatist rebels in eastern Ukraine who want to split with Kiev and become part of Russia.

The rebels have fought back, turning parts of the east into a war zone.

Who is Petro Poroshenko? Petro Poroshenko, 48, provided financial support to the revolt that brought down his Moscow-back predecessor, Victor Yanukovych. He is known as the "Chocolate King" after making his fortune as a confectionery manufacturer. He served in cabinet under Mr Yanukovych and also under previous governments led by Mr Yanukovych's foes. He was a former national security council chief, foreign minister and trade minister. This breadth of experience has given him a reputation as a pragmatist capable of bridging Ukraine's divide between supporters and foes of Moscow. Mr Poroshenko and former prime minister Yulia Tymoshenko traded accusations of corruption when both were in government following the "Orange Revolution" of 2004-05 that thwarted Mr Yanukovych's first bid for the presidency. But many voters saw him as less culpable than many in Ukraine of enriching himself illegally.



Where many "oligarchs" across the former Soviet Union took control of huge, formerly state-owned assets in the 1990s, many credit Mr Poroshenko with building his Roshen confectionery empire himself. In addition to his confectionery empire, Mr Poroshenko's other interests include a major TV news channel. Source: Reuters

On Friday they shot down a Ukrainian army plane and killed a member of the interior ministry's special forces in the separatist stronghold of Slaviansk, where residents said shelling continued all day.

Mr Poroshenko urged the pro-Moscow separatists to lay down their arms and said he would guarantee a safe corridor for Russian fighters to go home.

"I don't want war; I don't want revenge. I want peace and I want peace to happen," he said.

"Please, lay down the guns and I guarantee immunity to all those who don't have bloodshed on their hands."

Switching to Russian from Ukrainian to address the people of the troubled east, he said they had been duped by myths about the Kiev leadership which had been stoked by Russian propaganda.

He said he would soon visit them with guarantees of Russian-language rights and proposals for decentralisation that would give their regions a bigger say in running their own affairs.

In the days leading up to his inauguration, Mr Poroshenko met both US president Barack Obama, who warmly endorsed his leadership, as well as Mr Putin.

At a brief meeting in France, where they were attending World War II commemorations, French officials said Mr Poroshenko and Mr Putin shook hands and agreed that detailed talks on a ceasefire between Kiev government forces and the pro-Russian separatists would begin within a few days.

Russia denounced the overthrow of pro-Moscow president Viktor Yanukovych and has accused the Ukrainian authorities of worsening the crisis in the east by resorting to military force instead of dialogue.

It denies accusations by Kiev and Western governments that it is supporting the rebels.

Mr Putin told reporters he welcomed Mr Poroshenko's proposals for ending the conflict.

However, he declined to say what they were and said Ukraine must halt what he called "punitive" military operations against pro-Russian separatists.

The two countries are also at odds over the pricing of Russian natural gas, with Moscow threatening to cut supplies as early as next week unless Ukraine settles its debt, the amount of which is disputed.

Reuters