Ukrainian President Petro Poroshenko won his parliament's approval to shake up the leadership of the armed forces as they struggle to end a rebellion by pro-Russian separatists.
Parliament endorsed Colonel-General Valery Heletey as defence minister after hearing Poroshenko describe the 46-year-old as a man "who will work day and night for restoring the military capability of our armed forces".
He also named a new chief of the general staff.
Heletey, who will replace acting Defence Minister Mykhailo Koval, would enact reforms to build an army which would deter anybody "from planning aggression" against Ukraine, he said.
A photo of Heletey signing his oath of allegiance with a capped pen was ridiculed on the Russian news website RT.
The new head of the general staff, Lieutenant-General Viktor Muzhenko, 52, was until recently a top official in the "anti-terrorist operation" grouping the army and other security bodies in the drive against the rebels.
Poroshenko took office last month with the country in crisis, as two eastern regions press demands to break away and join Russia, following the example of Crimea earlier this year.
After months of unsuccessful attempts to quash the uprising, he wants to sharpen the army's effectiveness while exploring diplomatic options to end the crisis.
Poroshenko on Monday rejected a further extension of a 10-day unilateral ceasefire in the east, where the government says 200 soldiers have been killed since the start of the conflict, as well as hundreds of civilians and rebels.
In a telephone conversation with US Vice President Joe Biden, Poroshenko repeated a promise that Ukraine could return to the ceasefire, on three conditions.
A statement on his website said he wanted assurances on a "bilateral" truce, the release of hostages, and the deployment of international monitors to check Ukraine's porous border with Russia.
Russia denies Ukraine's charges that it is letting fighters and weapons cross into the east of the country.
French President Francois Hollande and German Chancellor Angela Merkel urged Russian President Vladimir Putin on Thursday to encourage the separatists to reach an agreement with the Ukrainian authorities, the French president's office said.
The governor of the Ukrainian town of Khmelnytsky was on Wednesday confronted and attacked at the regional administrative building by an angry crowd demanding his resignation, Reuters reported.
Leonid Prus was verbally and physically confronted by Khmelnytsky residents. The crowds chanted "resign" as the official stood amongst them - before the confrontation became physical.
Despite a police presence in the room, scuffles broke out and video footage shows Prus being hit and carried by the angry crowd.
The Khmelnytsky residents also scuffled with the police.
Prus was seen walking out of the office in a town jacket torn as he managed to leave the building through the window - only to be cornered by more residents outside.