George Bush was being interviewed on CNN's
George Bush was being interviewed on CNN's The Situation Room with Wolf Blitzer

Former US president George W Bush has defended Prism, the internet spying system whose existence was leaked by whistleblower Edward Snowden.

The controversial programme began under Bush's presidency in 2007 and continued under Barack Obama. It was kept secret from the public until Snowden leaked information about it to the Guardian and Washington Post.

Speaking to CNN, Bush mounted his first public defence of the programme, which allowed the National Security Administration (NSA) to track people's internet and email activity for surveillance purposes.

He said: "I put the program in place to protect the country. And one of the certainties is civil liberties were guaranteed.

"I think there needs to be a balance, and as the president explained, there is a proper balance."

Bush was speaking from Tanzania, where he and his wife Laura are renovating a health clinic.

When asked about Snowden, who leaked information about Prism and is currently attempting to seek asylum in another country, Bush said the whistleblower has "damaged the country [and] damaged the security of the country".

Bush suggested the Obama administration "will deal with" Snowden and the NSA crisis, and refrained from criticising his presidential successor, who has faced censure for breaching the privacy of US citizens.

"I don't think [the criticism] it does any good," he said. "It's a hard job. He's got plenty on his agenda. It's difficult. A former president doesn't need to make it any harder. Other presidents have taken different decisions; that's mine."

Where Edward Snowden has asked for asylum

'Mandela's legacy will last'

Bush was also asked about former South African president Nelson Mandela, who is currently in a critical but stable condition in hospital after suffering a reoccurrence of a lung infection.

"Sometimes, there are leaders who come and go", he said. "His legacy will last for a long time".

When reminded of how Mandela publicly criticised him over the war in Iraq, Bush replied: "He wasn't the only guy.

"It's OK. I made decisions that were the right decisions. History will ultimately judge. I never held someone's opinion against him; I didn't look at him differently because he didn't agree with me on an issue."

Bush and Obama were in Tanzania togther to lay wreath at at the site of the 1998 US embassy bombing in the city of Dar es Salaam.