(AP) — President Barack Obama's top counterterrorism adviser says the U.S. faces "serious and significant" cyberthreats that could compromise national security.

John Brennan says the administration is taking steps to improve cybersecurity and looking at the matter from an espionage and terrorism point of view. He says national security is something that's at risk.

Brennan isn't naming any country or individuals possibly behind cyberattacks. He was asked on NBC's "Meet the Press" about concerns that computer hackers in China have infiltrated computer networks.

Pfc. Raheen Tyson Heighter, of Bay Shore, was killed in Operation Iraqi Freedom. His mother has made it her mission to aid active-duty service members, veterans, first responders and Gold Star families. NewsdayTV's Virginia Huie reports. Credit: Randee Daddona; Photo credit: Cathy Heighter

'His sacrifice made a difference': Gold Star mother honors son's memory Army Pfc. Raheen Tyson Heighter, 22, of Bay Shore, was the first serviceman from Long Island killed in the Iraq War.

Pfc. Raheen Tyson Heighter, of Bay Shore, was killed in Operation Iraqi Freedom. His mother has made it her mission to aid active-duty service members, veterans, first responders and Gold Star families. NewsdayTV's Virginia Huie reports. Credit: Randee Daddona; Photo credit: Cathy Heighter

'His sacrifice made a difference': Gold Star mother honors son's memory Army Pfc. Raheen Tyson Heighter, 22, of Bay Shore, was the first serviceman from Long Island killed in the Iraq War.

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