Moscow and Kyiv's fraught relationship extends far beyond the battlefield in eastern Ukraine.

On Tuesday, Russia said it was unwilling to delay repayment of $3 billion (2.6 billion euros) in loans it provided the Ukrainian government more than a year ago before former pro-Moscow president Viktor Yanukovych was deposed.

"We are not ready to accept delay or payment in installments," Russian Finance Minister Anton Siluanov said on the sidelines of the G20 summit in Istanbul. "We are expecting and awaiting fulfillment of all obligations by Ukraine to Russia this December."

In December 2013, Russia agreed to provide Ukraine $15 billion in bailout loans to prop up that country's struggling economy. But it suspended payments after the first $3 billion installment following Yanukovych's ouster.

Siluanov said Moscow wasn't in a position to defer payment, particularly at a time when Russia's own economy is beset by a crumbling ruble and a slump in oil prices.

But he also made no mention of an early payment, something officials considered demanding last month, citing what they said were violations of loan conditions by Kyiv.

"Any budget income in foreign currency is important to us," Siluanov said.

sri/cjc (AFP, Reuters)