Representatives of two research laboratories funded by the US and a defence contractor were hit by a "highly sophisticated" cyber attack last week, according to a report by Reuters.
The organisations went offline as soon as they discovered the breach on last Friday. Work is still on to restore access to their external websites, said the representatives.
Pacific Northwest National Laboratory (PNNL) in Richland, Washington; Thomas Jefferson National Laboratory in Newport News, Virginia and Battelle Corp were the victims according to the report.
However, it is believed that hackers could not lay their hands on classified information.
PNNL spokesman Greg Koller said, "The good news is no classified information has been compromised or is in danger from this attack."
"At this time, we have not found any indication of ‘exfiltration’ of information from our unclassified networks as well," Koller added.
This week saw the launch of an international body to fight cyber crime. The International Cyber Security Protection Alliance (ICSPA) is an international not-for-profit body that has been formed to work for law enforcement cyber crime units across the world.
The US has stepped up efforts to fight cyber crime after hackers breached into several government websites including senate.gov and FBI.
Earlier, the Pentagon had said that it would consider all options if the US were hit by a cyber-attack, including a military response.
Pentagon spokesman Colonel Dave Lapan had said, "A response to a cyber incident or attack on the US would not necessarily be a cyber-response."
"All appropriate options would be on the table if we were attacked, be it cyber."
Recently, the White House had also unveiled an international strategy statement on cyber-security which said the US "will respond to hostile acts in cyberspace as we would to any other threat to our country."
"We reserve the right to use all necessary means — diplomatic, informational, military, and economic — as appropriate and consistent with applicable international law, in order to defend our nation, our allies, our partners and our interests," the strategy statement said.
