US president Barack Obama is cancelling his planned meeting with Russian President Vladimir Putin scheduled for next month in Moscow, an administration official said on Wednesday.

"Given our lack of progress on issues such as missile defense and arms control, trade and commercial relations, global security issues, and human rights and civil society in the last twelve months, we have informed the Russian government that we believe it would be more constructive to postpone the summit until we have more results from our shared agenda," White House spokesman Jay Carney said in a statement.

Obama will still attend a G20 summit in St Petersburg, but scrapped the one-on-one meeting partly because of Russia's decision to grant temporary asylum to former US spy agency contractor Edward Snowden.

"I was disappointed, because even though we don't have an extradition treaty with them, traditionally we have tried to respect if there's a lawbreaker or alleged lawbreaker in their country," Obama said of the asylum deal during an appearance on a late-night comedy show on Tuesday.

Obama noted that there have not been "major breaks" in the relationship with America's former Cold War foe.

"There's still a lot of business that we can do with them, but there have been times where they flip back in the Cold War thinking and in a Cold War mentality," Obama said.

Yuri Ushakov, Putin's foreign policy aide, told reporters that Obama's decision was "disappointing."

Washington had wanted Snowden home to face criminal charges, including espionage, for disclosing in June secret American internet and telephone surveillance programmes.

During the interview, Obama also said the recent threat that caused the United States to close embassies throughout the Middle East was significant.

"It's a reminder that for all the progress we've made ... this radical, violent extremism is still out there," Obama said. "We've got to stay on top of it."

The US State Department issued a worldwide travel alert on Friday warning Americans that al-Qaeda may be planning attacks in August, particularly in the Middle East and North Africa.