Mullah Abdul Ghani Baradar, a top Afghan Taliban military commander, has been captured in Pakistan, US officials say.

He was seized in a morning raid on a madrassa near Karachi by Pakistan's ISI intelligence service on February 8, a security source told the BBC.

The government has yet to confirm the arrest while the Taliban have denied it, saying Baradar is still in Afghanistan and leading the war.

The capture comes amid a major Nato-led offensive against the Taliban in southern Afghanistan.

While the raid on Madarassa Khuddamul Quran - near the Nooriabad Industrial Estate some 45km (28 miles) from Karachi - was led by the ISI, it is not clear at the moment whether US officials were involved.

Little is known about Mullah Baradar, but in terms of influence his rank is second in the outfit, next to the Taliban's spiritual leader, Mullar Muhammad Omar, who has been hiding from Western agencies since the 9/11 terror attacks in 2001.