The sentencing phase of Manning's court-martial is in its second week. He was convicted last week of 20 counts, including six Espionage Act violations, five federal theft counts and a federal computer fraud charge for leaking more than 700,000 documents from a classified government computer network while working as an intelligence analyst in Iraq in 2010. Manning says he leaked the material to expose wrongdoing by the military and U.S. diplomats. He contends he selectively leaked material that wouldn't harm service members or national security. At his sentencing hearing, prosecutors are presenting evidence that the leaks damaged U.S. interests. They have focused mainly on the impact of more than 250,000 State Department diplomatic cables that WikiLeaks began publishing in November 2010. Maj. Gen. Michael Nagata testified for the prosecution Tuesday that the leaked cables had an impact on U.S. military operations in Pakistan, where he was deputy commander of a defense office within the U.S. embassy in Islamabad. Nagata saved the details of the impact for a closed court session to protect classified information. The leaked cables publicly revealed a closer U.S.-Pakistani military relationship than Pakistan had publicly acknowledged. The cables also disclosed U.S. concerns Islamist militants could get their hands on Pakistani nuclear material to make an illicit weapon. One leaked cable revealed that instructors at a prestigious Pakistani defense institution were giving anti-American lessons to senior officers. U.S. officials said in 2010 the leaked cables may have endangered operatives inside Afghanistan and Pakistan who had worked against the Taliban or al-Qaida. However, Pentagon spokesman Geoff Morrell said at the time that cables implying some Pakistani intelligence officials were aiding insurgents were "clearly out of step with where this relationship is now, and has been heading for some time." Prosecutors also have presented evidence the disclosures damaged America's military and diplomatic relationships with some foreign governments and endangered the lives of foreign citizens who had confided in diplomats. Brian Manning, of Oklahoma City, said on CNN's Anderson Cooper 360 that he can't understand how someone could obtain so much classified information and smuggle it out of a supposedly secure workplace without being detected. Bradley Manning has said he downloaded the material onto his workplace computer, transferred it to CDs and then used his personal computer to send it to WikiLeaks. "He was used to running his life on his own, he was a man of the house, and he had problems adjusting to that, so I feel part of that was he had a lot of pride," Brian Manning said. A former Navy technician, Brian Manning said it would be wrong to leak classified information that would damage the United States and its military. He said he loves his son but that if he could speak freely with him, "I would basically tell him right off the bat that he had no excuse whatsoever for allegedly releasing that information." Brian Manning declined an Associated Press interview request Tuesday night. Copyright 2013 The Associated Press.