● The Haqqani network
Western officials say the Haqqani network may be the most dangerous insurgent group. It is centered around Jalaluddin Haqqani, another former US ally, whose son Sirajuddin has in recent years assumed leadership. The group usually operates independently of – though sometimes in concert with – the Taliban and Hizb-e-Islami. It is believed to be behind many of the boldest attacks in recent memory, including a 20-hour attack on Kabul in September 2011 and multiple assassination attempts on President Hamid Karzai.
Analysts say that, of all the insurgent groups, the Haqqani network has the closest ties to Al Qaeda. "Al Qaeda shares a symbiotic relationship with the Haqqani network," Matthew DuPee, a researcher on Afghan affairs at the Naval Postgraduate School in Monterey, Calif., told the Monitor.
The Haqqani network leadership is based in North Waziristan, in the tribal areas of Pakistan. It has a presence in eastern Afghanistan.
● Other 'Taliban'
Many criminals and warlords call themselves the Taliban, possibly to try to boost their legitimacy.
Some local groups also operate independently of the Taliban leadership: for example, Hizb-e-Islami Khalis in Nangarhar Province and others in Kunar Province, both of which are in the east.