The rouble reached 65.91 versus the dollar for the first time since Nov. 23 but later pared gains and traded at 66.02 as of 0937 GMT, up 0.1 percent on the day.
Venezuela came into focus after its opposition leader, Juan Guaido, declared himself interim president on Wednesday, winning the backing of Washington and many Latin American nations.
However, Russian officials condemned the move as illegal, raising concerns of more geopolitical tensions between Moscow and the West.
If Moscow supports President Nicolas Maduro, who has led the oil-rich nation since 2013, it may give the US Congress a reason to resume sanctions against Russia, said Kirill Tremasov, the head of research at Loko-Invest.
"Developments in Venezuela are certainly the key factor for markets in the coming days," said Tremasov, a former head of the forecasting department at the economy ministry.
Over the past few years, Moscow has become Venezuela's lender of last resort.
The Russian government and oil giant Rosneft have handed Venezuela at least $17 billion in loans and credit lines since 2006, according to Reuters calculations.
"The most unpleasant scenario for Rosneft now is the change of power in the country and the revision of contracts," said Dmitry Marinchenko, an analyst with Fitch Ratings in Moscow.
It should not be ruled out that Rosneft could lose up to about $3 billion of its prepayment for supplies of Venezuelan oil, Marinchenko said.
Rosneft shares underperformed the market, losing 2.6 percent on the day.
Russian stock indexes were mixed. The dollar-denominated RTS index was up 0.2 percent to 1,188.8 points. The rouble-based MOEX Russian index was 0.1 percent lower at 2,490.2 points.
ROUBLE OUTLOOK
The rouble retains support from high oil prices and month-end taxes that usually prompt export-focused companies to convert dollar revenues to meet local liabilities.
In the next few days, the rouble could strengthen to 65.70 to 65.80 against the dollar, said Artem Zvonarev, a trader at VTB Capital.
"Today exporters' support can still be felt, but in the longer term the rouble's dynamics and its direction will be more dependent on speculators and financial investors," said Dmitry Polevoy, chief economist at Russian Direct Investment Fund.
The rouble gained 0.5 percent to 74.88 to the dollar, its strongest since mid-December.
The rouble could reach 64.5 against the dollar in the first quarter, VTB Capital analysts said in a note, because the global environment is likely to support emerging markets.
Brent crude oil, a global benchmark for Russia's main export, was down 0.4 percent at $60.91 a barrel, trading away from its lowest level since mid-2017 of $49.93 it hit last month.