Osama bin Laden’s brand of terrorism continues to operate as a shadow government in tribal areas of Pakistan, said a report, six years after the death of the Al Qaeda leader by US forces in Abbottabad.

The report by the private intelligence firm Soufan Group says the ideology of the once global terrorist is spreading at a viral pace, reported Sputnik news on Tuesday.

"His [bin Laden’s] brand of terrorism is now at least a shadow form of government - if not an open one - in Iraq, Syria, Yemen, Afghanistan, and tribal areas of Pakistan, with no realistic cause for optimism in either the short or long term," the report stated.

It says the ideology is spreading as the US and its partners get more deeply involved in terror-related conflicts, most notably, against Islamic State, which essentially follows the same violent ideology of bin Ladenism.

The report concluded that attempts to counter the bin Laden ideology will continue to represent a primary counterterrorism challenge for the foreseeable future.