Teachers in the north-western Pakistani province of Khyber Pakhtunkhwa have gone on indefinite strike.
They want to put pressure on the government to negotiate the release of a university lecturer being held by the Pakistani Taliban.
Dr Ajmal Khan, the vice-chancellor of the Islamia College University in Peshawar, was kidnapped from his campus residence on 7 September.
On 7 October a video purportedly of him was released by the Taliban.
It showed Dr Khan appealing to the government to negotiate his release with members of the Tehrik-e-Taliban Pakistan (TTP).
He also appealed to the teacher and student community to put pressure on the government over his abduction.
The doctor made a similar appeal in another video released on Sunday.
In that he said that the Taliban had given him until 20 November to persuade the government to negotiate his release.
"If their [the TTP] demands are not accepted by 20 November, then I will not remain in this world," he said in the video, reading from a written text in the Urdu language.
Senior members of Pakistan's Teachers' Association called an emergency meeting hours after the video was aired to declare an indefinite strike in universities in Khyber Pakhtunkhwa - the province which until recently was known as North West Frontier Province.
The association said that if quick action was not forthcoming from the government, the strike may be extended to universities all over the country.
Reacting to the video, provincial information minister Mian Iftikhar Hussain said that his government would do everything to secure Dr Khan's release.
"We have always done everything possible to secure the release of kidnapped persons, and we will do our best in this case as well," he said in a press release issued on Sunday night.
The TTP have not made clear their demands, but it is understood they want the release of some of their detained leaders in return for Dr Khan's release.