WASHINGTON  - President Barack Obama defended secret US security programmes late Monday and rejected comparisons with predecessor George W Bush, even as rogue intelligence tech Edward Snowden warned that more leaks are on the way.

The Obama administration has been on the defensive since last week’s dramatic leak of details of two huge operations by the National Security Agency to track US citizens’ phone calls and intercept global Internet traffic.

The Internet surveillance controversy was such that North Korea, one of the world’s most repressive societies, on Tuesday took the opportunity to brand the United States a “kingpin” of human rights abuses, in the government’s official Minju Joson newspaper.

Obama pushed back in a TV interview to charges that he had merely continued with the surveillance policies that ex-president Bush and former vice president Dick Cheney had brought in after the September 11, 2001 attacks.

Obama said on the “Charlie Rose” show on PBS television that the NSA data-gathering programmes were carried out with “systems of checks and balances,” and insisted that “Congress is overseeing it, federal courts are overseeing it.” “My concern has always been not that we shouldn’t do intelligence gathering to prevent terrorism, but rather - are we setting up a system of checks and balances?”

Obama also said he recognized the “legitimate concern” raised by news reports, and that he had ordered intelligence officials to declassify as much as possible “without further compromising the programme.” He also promised that an independent advisory board would review the programmes.

The leaks indicated that the NSA and FBI get vast amounts of data from US Internet companies, to allow for round-the-clock monitoring of emails, documents, video, social media posts and photos online.

Another programme gathers mountains of call data from major telecom operators. This Internet snooping controversy, along with others, have hurt the president’s approval rating, which have fallen by eight points. Some of Obama’s progressive allies have also joined attacks against him by his usual conservative and libertarian opponents.

Meanwhile Snowden, the 29-year-old former NSA contractor who triggered the firestorm, issued a defiant rebuke to his critics in Washington Monday, and warned of more leaks.

Snowden, who fled last month from his job at an NSA base in Hawaii to Hong Kong carrying with him a cache of secret documents, said in an online interview hosted by The Guardian newspaper that “More detail on how direct NSA’s accesses are is coming.”

Firms like Google and Facebook say they provide information only when presented with a court order, and deny that they have effectively given the NSA “back door” access directly to their data banks.

Yahoo! said in a letter to users late Monday that it has received up to 13,000 requests for information from US law enforcement agencies in a six-month period ending May 31. According to the letter, the most common requests “concerned fraud, homicides, kidnappings, and other criminal investigations.”

But Snowden repeated his claim that almost any intelligence analyst with access to the NSA signals intelligence database could target almost anyone’s emails or phone metadata and that warrants are rarely audited.

Snowden alleged that Americans’ communications were collected and consulted on a “daily basis,” with analysts having access to all details associated with a targeted email address, such as IP addresses, raw data, content, headers and attachments.

“The restrictions against this are policy-based, not technically-based, and can change at any time,” he said.

Snowden also rejected allegations that he was a Chinese spy.

“This is a predictable smear that I anticipated before going public,” he said. “Ask yourself: If I were a Chinese spy, why wouldn’t I have flown directly into Beijing? I could be living in a palace petting a phoenix by now.”

Since Snowden surfaced in Hong Kong, he has released details of several US snooping programmes. In the latest, he embarrassed the British government on the eve of the G8 by revealing that it had bugged leaders at a previous summit.