Vladimir Putin praised Cold War era scientists on Thursday for stealing U.S. nuclear secrets

(Reuters) - Vladimir Putin praised Cold War-era scientists on Thursday for stealing U.S. nuclear secrets so that United States would not be the world's sole atomic power, in comments reflecting his vision of Russia as a counterweight to U.S. power.

Spies with suitcases full of data helped the Soviet Union build its atomic bomb, he told military commanders.

"You know, when the States already had nuclear weapons and the Soviet Union was only building them, we got a significant amount of information through Soviet foreign intelligence channels," Putin said, according to state-run Itar-Tass.

"The were carrying the information away not on microfilm but literally in suitcases. Suitcases!"

Putin's remarks referred to the dawn of the Cold War more than half a century ago, but they echoed a message he has made loud and clear more recently: that the United States needs to be restrained, and Russia is the country to do it.

It has been known for decades that there were spies among the scientists who worked on the Manhattan Project, the U.S. atomic bomb design operation. Putin suggested those who helped Moscow build its bomb acted out of concern for humanity.

"It was the cream the scientific world that was gathered in America, and I personally have gotten the impression that they consciously gave us information on the atom bomb," Putin was quoted as saying.

"They did this consciously because the atom bomb had been used on Hiroshima and Nagasaki and scientists from mankind's intellectual elite at the time understood what unilateral possession of such a weapon might lead to."

A need for Russia to act as a counterweight to U.S. power has been a continuous theme of Putin's time in office since he - himself a former Soviet spy - became president in 2000. He stepped down in 2008 to become prime minister but is poised to reclaim the presidency in an election on March 4.

Last year he criticized the United States for helping Libyan rebels oust Muammar Gaddafi. Lately he has suggested Washington has similar designs on Syria, where Russia has vetoed U.N. action. Earlier this month Putin said the world faced a growing "cult of violence".