U.S. research universities increasingly have become targets for cyberattacks, with millions of hacking attempts made weekly, university officials said. Officials concede some of the hacking attempts -- most of it thought to be from China -- have succeeded, but declined to reveal anything about the breaches except for those involving the theft of personal data, The New York Times reported Tuesday. They also acknowledge they often don\'t know of the breaks until much later, if ever. Plus, university officials said they may not be able to detect what was taken even if the breach is discovered. \"The attacks are increasing exponential, and so is the sophistication and I think it\'s outpaced our ability to respond,\" said Rodney Petersen, head of the cybersecurity program at Educause, a non-profit alliance of schools and technology companies with offices in Washington, D.C., and Colorado. \"So everyone\'s investing a lot more resources in detecting this, so we learn of even more incidents we wouldn\'t have known about before.\" Tracy B. Mitrano, Cornell University\'s information technology policy director, said detection was \"probably our greatest area of concern.\" She and others said that while most of the attacks seemed to have been initiated in China, hackers have become skilled at bouncing their work around the world, the Times said. The newspaper said a request for comment from the Chinese Embassy in Washington was not immediately answered. Bill Mellon of the University of Wisconsin said he was shocked at the volume of hacking attempts when he began overhauling computer security. \"We get 90,000 to 100,000 attempts per day, from China alone, to penetrate our system,\" said Mellon, associate dean for research policy. \"There are also a lot from Russia, and recently a lot from Vietnam, but it\'s primarily China.\" Other universities also report a similar number of attacks and say the figure is doubling every few years, the Times said.