Russia's need to import more gasoline after Ukrainian drone attacks on refineries will not weaken the rouble because exports of surplus crude oil will also increase, a top central bank official said on Thursday.

Russia has begun importing gasoline by sea from India and plans to import 400,000 metric tons a month from various countries to ease shortages that have led to long queues at filling stations.

According to Reuters calculations based on market prices, those imports could cost about 60 billion roubles ($767 million) a month.

Higher imports increase demand for foreign currency and can put pressure on the rouble. However, Andrei Gangan, head of the central bank's monetary policy department, said rising exports of crude that can no longer be processed domestically would offset the effect.

"Indeed, there will be some increase in imports under this category, but the volumes should not be significant enough to fundamentally alter the trends that are emerging in trade flows," Gangan said.

The rouble is seen as overvalued, with officials attributing its strength in part to Russia's distorted trade balance and weak imports, which reduce demand for foreign currency.

The rouble has weakened gradually in recent weeks, losing about 10% against the dollar since the start of June.

It strengthened 1.5% on July 1 after the central bank said there was less room for further cuts to its key interest rate. The bank also warned that rising fuel prices posed a risk to inflation.

($1 = 78.2000 roubles)