The ruble slipped in early trade on Friday, falling back after strong gains earlier in the week as traders repositioned before the weekend, though it could benefit later in the session from currency sales for tax payments.
At 0747 GMT, the ruble was around 1 percent weaker against the dollar at 57.88 and lost 0.6 percent to trade at 62.70 versus the euro.
Brent crude oil, a key driver for all Russian assets, was trading more than 1.5 percent down on the day at around $58.2 but was still more than 5 percent higher than at the start of the week.
The last major monthly tax, profit tax, falls due on March 30, and exporters are expected to sell hard currency on Friday to make the payments.
After the tax period ends, analysts say the ruble could weaken following gains of over 2 percent against the dollar this week, not least because it remains vulnerable to volatility in oil prices.
"With the end of regular forex sales as part of the tax period, there will appear clear factors for the ruble to weaken — the instability of oil and possible halt to the rally in OFZs (Russian treasury bonds)," analysts at Rosbank said in a note.
Russian shares were also weaker on Friday, extending losses from the previous session.
The dollar-denominated RTS index was down 0.8 percent to 861 points while its ruble-based peer MICEX traded flat at 1,582 points.