MOSCOW, Nov 21 (Reuters) - The Russian rouble strengthened to a five-week high against the U.S. dollar on Friday on renewed expectations of a peace in Ukraine, following reports about a U.S.-backed plan aimed at settling the conflict.

At 1130 GMT, the rouble was more than 1.3% stronger at 79.00 against the dollar in over-the-counter trade and 1.2% stronger at 11.07 against the yuan on the Moscow Stock Exchange, where it is the most traded foreign currency.

The rouble hit 78.55 to the dollar during the trading session, its strongest level since October 16.

The rouble strengthened despite U.S. sanctions on Russian oil firms Rosneft and Lukoil, which take effect at 1701 GMT on Friday. The sanctions are expected to reduce foreign currency inflows, which have been supporting the rouble.

"After the introduction of sanctions, foreign currency revenues from oil exporters may decrease by about 10–15%, which could reduce the supply of foreign currency on the domestic market," said Alexander Potavin from Finam.

"From a long-term perspective, the reduction of foreign assets and strict external sanctions lead to higher costs in export supply chains and lower foreign currency revenues, which is negative for the rouble," he added.

(Reporting by Gleb Bryanski
Editing by Ros Russell)

((gleb.bryanski@thomsonreuters.com;))