MOSCOW - Russian President Vladimir Putin on Thursday described US surveillance programs as a necessity to fight terrorism but also expressed admiration for fugitive Edward Snowden over his leaking of the schemes.

Speaking during his marathon annual press conference, Putin denied he had ever met former US National Security Agency (NSA) contractor Snowden who now has refugee status in Russia.

"I don't know Mr. Snowden, never met him. I have a lot of things to do," Putin said.

But he added: "He's not uninteresting to me. Thanks to him, millions of people, including political leaders, have changed their minds on a variety of issues... That is his accomplishment."

Putin once again denied that Snowden was ever questioned by Russian intelligence officers and said that he is staying in Russia as long as he doesn't engage in "anti-American propaganda."

"We are not working with him and never have, we don't bother him with questions regarding what was done vis-a-vis Russia by the agency where he worked," Putin said.

Putin said however the spying is a "necessity" and added that he "envies" US President Barack Obama.

"He can do this and have no consequences," Putin said of the spying.

"As much criticism as our American friends face, I think all this work is done primarily to fight terrorism," he said, adding that despite everything "all in all, it is a necessity."

"You have to follow not just one terrorist suspect, but the entire network of his contacts," he said. "That is next to impossible by only spying on one suspect."

"Espionage is one of the oldest professions," said Putin, himself a former KGB spy, drawing laugher from the audience of hundreds of journalists.

"I am not defending anyone, but to be fair, it's all done primarily to fight terror," Putin said.

Snowden made a series of leaks about global US surveillance programs after quitting his job as a contractor for the NSA and then attempted to flee to South America only to get stuck in a Moscow airport.

In August he was granted one-year asylum status by Russia and is living in an undisclosed location. Recently his Russian lawyer said he had started working for a major website to earn some money after running out of cash.

His leaks showed that the United States had spied on state leaders, including German Chancellor Angela Merkel, causing a diplomatic scandal. They also alleged that NSA technicians had tapped into Yahoo and Google data centers around the world, winning access to vast amounts of private data.

Evidence of Snowden's life in Russia had been scant, with leaked photos showing him grocery shopping, on a Moscow river boat ride, as well as at an unidentified hotel where he accepted an award from a group of US whistleblowers who travelled to Russia to meet him.

Putin indicated he believed that Snowden's life circumstances were not easy.

"He made this choice. It's honorable but difficult," Putin said. "What does he have? Nothing. How does he plan to live? Where does he plan to live?"