Pro-Russian separatists have targeted Privatbank, after its co-owner, billionaire Igor Kolomoisky, was appointed by the new government head of the nearby Dnipropetrovsk region and swiftly announced a $10,000 bounty on the heads of Russian "saboteurs."
Rebels, who say they want independence from Kiev, set fire to a branch in the town of Mariupol in the Donetsk region late on Saturday and raided a security truck last week in Horlivka, south of the region's main rebel stronghold.
"In the current circumstances we cannot and do not have the right to make people go to work in the Donetsk and Luhansk regions, where armed people break into bank branches and seize security vans in the towns," Privatbank said in a statement.
It said its clients could access their accounts via the Internet and mobile devices, use their cards in shops and make cashless transactions at self-service terminals.
"Over the last 10 days, 38 ATMs, 24 branches of Privatbank and 11 cash collection vans have suffered arson, assault and wanton destruction in the cities of Donetsk and Luhansk," it said, adding that the bank processes more than 400,000 pensions and other social benefits for 220,000 people in both regions.
Kolomoisky, Ukraine's fourth-richest man, according to Forbes magazine, has become a figure of hate for pro-Russian separatists after he said he would give $10,000 to Ukrainian troops for every "saboteur" handed over.
Dnipropetrovsk has been calm since separatists started taking control of wide swathes of the Donetsk and Luhansk regions last month, in an operation blamed on Moscow by Kiev's new pro-Western leaders.
Russia, which has long considered Slavic Ukraine an extension of its own country, denies any involvement in the unrest, saying Russian speakers are simply protecting their rights from attacks by a hostile government.
Privatbank has suffered a series of setbacks since protests in Kiev ousted former Ukrainian President Victor Yanukovych in late February. The bank sold its Russian subsidiary in April, weeks after Kolomoisky branded President Vladimir Putin "unhinged." The bank has also pulled out of Crimea, where it had 337 branches, after Russia annexed the peninsula in March.
Material from the Moscow Times was used in this report