MOSCOW - Russia showcased its military might and youthful new president for the world Friday, as heavy tanks and missile launchers rumbled across Red Square in a Victory Day parade for the first time since the Soviet era.

In a nationally broadcast speech two days after his inauguration, President Dmitry Medvedev avoided the bellicose rhetoric of his mentor and predecessor, Vladimir Putin, who drew parallels between United States and Nazi Germany during last year's parade.

However, in his speech marking victory over Adolf Hitler's Germany, Medvedev, 42, said the history of World War II demonstrated that military conflicts are rooted in "irresponsible ambitions which prevail over interests of nations and entire continents.

"We must not allow contempt for the norms of international law," he said, in what sounded like veiled criticism of the United States and its Western allies.

Putin, who was named prime minister Thursday, hovered at Medvedev's shoulder on the podium. His face was prominent on TV -- an image that played to the wide belief the former president will continue calling the shots.