Updated at 2:24 p.m.

Former president Jimmy Carter said Sunday that President Obama has not sought his advice on foreign policy and how to deal with the Russian aggression in annexing Crimea.

"There has to be a concerted international effort against Putin going any further," Carter said in an interview with NBC's Andrea Mitchell that aired Sunday morning on "Meet the Press," in which he discussed his new book "A Call to Action."

Mitchell then asked if Obama has asked Carter for any advice in handling Russia, and the former president responded:

"Unfortunately the answer is no. President Obama doesn't, but previous presidents have called on me."

Carter also said during the interview that he does not use e-mail when contracting foreign leaders and dignitaries, in part because he believes those communications may be monitored by the National Security Agency.

“My own communications are probably monitored,” Carter said. "When I want to communicate with a foreign leader privately, I type or write the letter myself, put it in the post office and mail it, because I believe if I send an e-mail, it will be monitored."