The new Ukrainian president, Petro Poroshenko, has been sworn, setting out a plan to bring peace to the conflict-torn east of the country.
The 48-year-old tycoon, who won the 25 May election, offered political concessions to people in the east and said he did not want war or revenge.
But he also said he had told Russia's president that Crimea, which Moscow has annexed, would "always be Ukrainian".
Kiev accuses Moscow of backing armed militants in the eastern Donbass area.
Russia denies the allegations.
Mr Poroshenko was inaugurated in the presence of dozens of foreign dignitaries - including US Vice-President Joe Biden - in parliament in the capital Kiev.
Mr Poroshenko, the owner of the Roshen chocolates group, took the oath of office and laid out a programme for ending the crisis that included an offer of early regional elections in the east and a decentralisation of power to the regional administrations.
He said: "I don't want war. I don't want revenge, despite the huge sacrifice of the Ukrainian people."
Ukraine's President Petro Poroshenko Photo: AFP
Mr Poroshenko called on separatists in the east to lay down their arms, saying he would guarantee indemnity from criminal charges to all those who did not have blood on their hands.
But he added: "Talking to gangsters and killers is not our path."
The BBC's correspondent in Kiev reports part of the speech was in Russian - directed at those in strife-torn Donbass - and offered concessions on Russian language and a corridor for Russian fighters to return home.
There were standing ovations for the president's comments on Crimea and on ties with the European Union - which he reiterated he wanted Ukraine to join.
Mr Poroshenko condemned the rule of former President Viktor Yanukovych, seen by many as pro-Russian, who fled in February after a popular uprising in Kiev.
He accused Mr Yanukovych of financing terrorism in the east, saying he was "fully responsible for the situation there today".
