Ukrainian President Petro Poroshenko on Friday fired a prominent business baron as governor of the war-torn eastern region of Donetsk and appointed a former troop commander in his place.
Sergiy Taruta was one of several pro-Western tycoons whom the interim authorities in Kiev put in charge of restless Russian-speaking regions shortly after their February ouster of a Kremlin-backed president.
Poroshenko's office said Taruta has been replaced by former interior ministry troop commander Oleksandr Kykhtenko.
Analysts said the former general's appointment means Poroshenko will now be more focused on security issues rather than political negotiations with insurgency leaders and the Kremlin.
Taruta's authority was challenged in April by separatist guerrillas who seized his Donetsk seat of power and proclaimed independence and allegiance to Russia.
The 59-year-old oil and metals magnate - valued at $600 million (475 million euros) by Forbes magazine last year - rejected the rebels' authority and tried repeatedly to mediate an end to the conflict.
But he reportedly angered Poroshenko for criticising the president's decision to give separatist-run swathes of the east limited autonomy in exchange for their agreement to halt fire and stay part of Ukraine.
Taruta demanded that martial law be proclaimed in Donetsk and the neighbouring separatist region of Lugansk - a decision Poroshenko resisted because it would have automatically frozen the delivery of an urgent IMF rescue loan.
The pro-government Ukrainska Pravda news site speculated that Poroshenko made up his mind earlier this week when Taruta congratulated Russian President Vladimir Putin on his 62nd birthday.
Kykhtenko will be immediately tasked with making sure that the industrial province can safely open polling stations for October 26 general elections that militias have vowed to disrupt.
The separatist command intends to stage its own polls next month that Kiev and its Western allies have denounced as illegitimate and in violation the terms of a shaky September 5 peace deal.
Kykhtenko heads the parliamentary election list of a small nationalist party called Strength and Honour.
His party colleague Igor Smeshko was recently named Poroshenko's surveillance and intelligence adviser.
"Today, the region needs a military commander rather than an administrator," said Kiev political analyst Taras Berezovets.
"In my opinion, Ukraine has lost control over the area for the next five or 10 years, and now he needs to make sure it does not turn into another Chechnya," he said in reference to a separatist southern region of Russia that remained lawless for nearly 20 years.