"We don't recommend using the Internet for communication, not even via an encrypted channel, even though we understand that Edward is an IT expert," RIA Novosti news agency quoted Anatoly Kucherena as saying.

　　Still, Lon Snowden's fatherly feelings "proved stronger than security awareness," Kucherena said.

　　Earlier media reports said Lon Snowden had contacted his son using encrypted messages. Previously, the father communicated with his son only via his lawyer Kucherena.

　　According to the lawyer, Snowden is taking an adaptation course in a safe place, and "he is missing his family."

　　The former National Security Agency (NSA) leaker's father said Saturday he had secured documents to visit the whistleblower in Russia, where the son has been granted a year's temporary asylum after spending almost seven weeks stranded in Moscow's Sheremetyevo airport because Washington revoked his passport.

　　Snowden faces espionage charges in the United States after disclosing a classified intelligence surveillance project code-named PRISM.

　　Russia's decision on Aug. 1 to grant him asylum in the face of calls by the the U.S. to return him for a trial has cooled U.S.-Russian relations and prompted President Barack Obama to cancel a scheduled meeting with counterpart Vladimir Putin in September.