Washington, Dec 22 : Hackers in China have reportedly been able to break into the systems at the United States Chamber of Commerce, the country''s largest business-lobbying organization.

All the data held by systems, including information about its 3million members, are said to have been left vulnerable after the infiltration, The Daily Mail reports.

The Chinese embassy in Washington, however, denied that their government was behind the attacks, dubbing the allegations ''irresponsible''.

According to a Wall Street Journal report, the security breach, which involved the infiltration of at least 300 Internet addresses, was found last year and quietly shut down.

After a tip off from the FBI, computer security experts at the Chamber shut it down by unplugging and destroying some computers, the report said.

Nevertheless, it is understood that hackers might have access to the network for more than a year before the hack was discovered.

According to the report, it is still unclear that how much of the compromised data was actually viewed.

Sources close to the Chamber''s investigation said that hackers had focused on four employees working on Asia policy, stealing six weeks'' worth of their email records.

They said that the emails revealed names of key firms and individuals in contact with the Chamber, policy documents, meeting notes, trip reports and schedules.

If reports suggesting that the hack is carried out by China turns out to be true, then the hack would be one of the boldest attacks yet in what has become an ongoing battle between Chinese hackers and companies and U. S agencies. (ANI)