MOSCOW. April 8 (Interfax) - Oleg Deripaska, the co-owner of Russian aluminum giant United Company RUSAL, has said he is concerned about the rapid appreciation of the ruble.

"The main problem for us is not inflation but the strengthening of the ruble. We can't do anything about inflation, but the ruble's appreciation is within our powers," Deripaska said on Tuesday at a meeting between Russian president-elect Dmitry Medvedev and the heads of the Russian Union of Industrialists and Entrepreneurs (RUIE).

"The rates of the ruble's appreciation are not justified at all, nobody can explain them," he said.

Medvedev said earlier at the meeting that inflation is a "serious problem" and the government should use various tools to minimize its impact on the economy.

"We should have a look at instruments that can be used to lessen the impact of inflation on our economy and the incomes of our citizens," Medvedev said.

Measures to slow down inflation rates have been taken over the past year, he said. However, "we face a rather serious problem," Medvedev said.

Medvedev said he took a look at several economic surveys before the meeting. "The majority of analysts believe that the world has entered a belt of high inflation. This is a great threat," he said.