New Ukrainian Defence Minister Valeriy Heletey has promised that the army would retake Crimea, restoring the country's territorial integrity.

Addressing parliament in Kiev, he said: "There will be a victory parade... in Ukraine's Sevastopol."

Russia annexed the peninsula - which has a Russian-speaking majority - in March after a controversial referendum.

In eastern Ukraine, a government offensive against pro-Russian separatists is continuing.

German Chancellor Angela Merkel and French President Francois Hollande have urged Russian President Vladimir Putin in a conference call to use his influence to put pressure on the rebels in the Donetsk and Luhansk regions.

Mr Putin said he was "deeply concerned about the rise in deaths among the civilian population and sharp increase in refugees" entering Russia from south-eastern Ukraine, according to the Kremlin.

All three leaders agreed that the Organization for Security and Co-operation in Europe (OSCE) should play a more active part in monitoring the situation in the conflict zone.

Ukrainian President Petro Poroshenko later said he was ready to return to a ceasefire provided it was observed by both sides, all hostages were freed and borders secured by government forces.

His statement came after he spoke on the phone with US Vice-President Joe Biden. Mr Poroshenko called off a unilateral truce on 30 June, accusing the rebels of staging deadly attacks on Ukrainian government troops.

BBC