Pakistani troops have recovered a prominent academic held for four years by the Taliban in the country's troubled northwest, officials have said.

The Pakistani Taliban abducted Ajmal Khan, vice-chancellor of Islamia College University Peshawar, the capital of Khyber Pakhtunkhwa province, in September 2010.

A senior security official in Peshawar told the AFP news agency that Khan was recovered on Friday from "an operational area in North Waziristan tribal district".

The Pakistani military has been waging a major assault against Taliban strongholds in North Waziristan since mid-June.

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A statement from the Pakistan military to Al Jazeera said "security forces safely recovered Mr Ajmal Khan" but gave no details of how he was freed.

It said: "Security forces and intelligence agencies were trying to locate Ajmal Khan since 8 September 2010 when he was kidnapped in Peshawar while he was going to the university."

Ajmal had appeared in several video messages asking the government to negotiate his release with Pakistan's Tehreek-e-Taliban.

Government officials said despite many rounds of back-channel talks in the past, the Taliban had refused to release Khan, demanding the release of important Taliban commanders held by security forces.

Pakistan rights activists, university teaching staff and students in the northwest had all protested against Khan's kidnapping in the past.

Source: Al Jazeera and agencies