Yekaterina Matyushchenko, the finance minister in the Donetsk region's separatist government, said pension payments to retirees in the rebel-controlled areas will total 1.9 billion rubles (over $30 million) in March.
Another rebel official, Oksana Taran, denied that Russia had provided the money, claiming that the funds came from taxes paid by local businesses.
Ukraine's move in November to halt pensions and other social payments to the rebel-controlled territories in the east has hurt the region hard.
Local residents have to travel to government-controlled areas to receive payments, which is difficult given an effective government blockade of the east.
The pensioners' reaction to the payments was mixed.
One retiree, Viktor Medvedev, said while the payment had less value than his original pension in Ukrainian hryvnias, he was happy to have it.
"It's certainly not much, but what we can do? I'm glad to have at least this."
Another pensioner, Elena Ivanovna, was disappointed with Wednesday's payment, saying it was smaller than she expected.
"They told us we'll receive more," she said.
"Can you survive with this money?"
A separatist insurgency flared up in eastern Ukraine last April following Russia's annexation of Ukraine's Crimean Peninsula.
More than 6,000 people have died in fighting, according to the United Nations.
Russia and the rebels expected Ukraine to resume pensions and other payments to the east following February's cease-fire deal, but the Ukrainian authorities haven't yet done so amid fierce arguments over the agreement's interpretation.
The truce has largely held despite sporadic clashes, and the parties have pulled back their heavy weapons from the front line.
But other provisions of the deal have stalled.