WASHINGTON: The United States fingered emerging superpower China and resurgent Russia as main challengers on Tuesday in new intelligence guidelines that highlighted the rising scourge of cyber-war.

"China shares many interests with the United States, but its increasing natural resource-focused diplomacy and military modernization are among the factors making it a complex global challenge," said the 2009 National Intelligence Agency Strategy (NIS) document.

Releasing guidelines for the next four years, intelligence director Dennis Blair said they elevate "the importance of the challenges we face in the cyber domain," and singled out China as "very aggressive in the cyberworld." His strategy review, the first since 2005, warned that the Internet was "neither secure nor resilient" and recommended measures "across the cyber domain to protect critical infrastructure." The Russians also came in for criticism on the cyber threat issue and the intelligence document noted that Moscow's intentions on the world stage remained unclear.

"Russia is a US partner in important initiatives such as securing fissile material and combating nuclear terrorism, but it may continue to seek avenues for reasserting power and influence in ways that complicate US interests," it said.

The strategy document highlighted combating violent extremism and countering the proliferation of weapons of mass destruction as the top two goals of the US intelligence community.

Blair, a former commander of US forces in the Pacific from 1999 to 2002, said the US was targeting Al-Qaeda more aggressively because it had built up years of intelligence.

"What has really made all the nations safer has been the accumulation of knowledge about Al-Qaeda and its affiliate groups which enables us to be more aggressive in expanding that knowledge and stopping things before they happen." Blair made no allusion to recent US military successes but his remarks came the day after a surgical US strike in Somalia killed top Al-Qaeda fugitive Saleh Ali Saleh Nabhan.

Last month Pakistan Taliban chief Baitullah Mehsud was killed in a US drone attack, reportedly as he was getting a leg massage on the roof of his father-in-law's house.

"I say we are more aggressive and the ability to be more aggressive is founded on the much larger and more sophisticated understanding of the adversary we have gained across various administrations in recent years," Blair said.

The NIS strategy review also dished out harsh criticism on Iran and North Korea, where rulers are defying Western attempts to force them to abandon proscribed nuclear activities.

"Iran poses an array of challenges to US security objectives in the Middle East and beyond because of its nuclear and missile programs, support of terrorism, and provision of lethal aid to US and coalition adversaries.

"North Korea continues to threaten peace and security in East Asia because of its sustained pursuit of nuclear and ballistic missile capabilities, its transfer of these capabilities to third parties, its erratic behavior, and its large conventional military capability," it said.

Blair is only the third director of national intelligence.

The position was created by Congress in 2004 after investigations revealed that turf-sensitive intelligence agencies failed to share information that might have averted the September 11 attacks. That failure was followed by US intelligence's fateful error on Iraq's weapons of mass destruction.