MOSCOW  Russia’s president, Dmitri A. Medvedev, warned Friday that Russians had lost their sense of horror over Stalin’s purges, and called for the construction of museums and memorial centers devoted to the atrocities, as well as further efforts to unearth and identify the dead.

Mr. Medvedev made the comments on his video blog, on the occasion of a holiday devoted to the memory of victims of repression. He warned that revisionist historians risked glossing over the darker passages of the Soviet past, citing a poll that showed that 90 percent of young people could not name victims of the purges.

“Even now we can hear voices saying that these numerous deaths were justified by some supreme goals of the state,” Mr. Medvedev said. “Nothing can be valued above human life, and there is no excuse for repressions.”

Millions of people were killed under Stalin as a result of forced collectivization, deportation of ethnic groups, imprisonment in the Gulag and party purges, among other tactics.