"I'm out of politics. I have no plans whatsoever. This is my last stop," Kerry told CNN in an interview that aired Wednesday. "I'm going to serve the country in the extraordinarily privileged position the president's given me, the great challenges that I have, and move on."
And, he said, "I don't have to comment and won't comment on anybody contemplating or running for office anywhere."
In the interview, Kerry said the policy for Syria hasn't failed, but is "very challenging and very difficult." James Clapper, National Intelligence director, had said Syrian President Bashar Assad has been strengthened since the chemical weapons deal with Western countries and a U.N. report said his regime was torturing children.
"It's sort of a stalemate at this moment," Kerry said. "And there is increased capacity in some of the opposition; there is continued fighting among some other of the opposition."
Without providing details, Kerry said, "I will say to you that the President has taken an aggressive position."
"There are things the United States is doing right now, and everybody knows we are providing non-lethal assistance to the opposition in significant amounts," the secretary said. "We have taken the leadership with respect to bringing our allies together in efforts to be able to coordinate the operations that are taking place there. [The] president is always re-evaluating this. But I assure you, the United States is doing a great deal."
Kerry said he believed it would be a "mistake" for the United States to impose more sanctions against Iran as it and several other countries were negotiating terms concerning the Islamic republic's nuclear program the West believes is being used to develop a nuclear weapon.
"The United States of America agreed, together with our P5+1 allies -- with Russia, China, France, Great Britain, Germany -- all of them agreed that during the time we're negotiating we would not increase sanctions," Kerry told CNN. "We've lost nothing off the table, but we want to give diplomacy a chance, and we think that's worthwhile."
Kerry also was asked about the possibility of an extradition request concerning U.S. student Amanda Knox and her second conviction in Italy in the 2007 death of British student Meredith Kercher, Knox's roommate when the two were studying at an Italian university. Knox, who remained in her hometown of Seattle during the second trial, could face extradition back to Italy to serve a prison sentence. Her boyfriend at the time of Kercher's death also was convicted again.
"It's an ongoing legal process. There's nothing in front of us now, and I don't have to comment on it now and I'm not going to," Kerry said. "We'll let the legal process work out, and if and when the time comes that there's a reason that I have to comment, I'll do my duty."
Concerning the security of the 2014 Winter Olympics that start this week in Sochi, Russia, Kerry said if people want to go to the Games, by all means, go.
"I believe that anybody who wants to go to the Olympics, which are just a great event, should go," he said. "I think it will be as safe as you can make any large public event in a place where obviously we all know there have been some threats of late."