Pakistan's army has condemned the killing of an outspoken critic of the country's political and military leaders, saying state security forces were not responsible for his death.

Tuesday's reaction by an army spokesman, Maj. Gen. Asif Ghafoor, said it was "ill-intended propaganda to implicate state agencies" in the activist Mohammad Bilal Khan's death.

Khan was stabbed to death on Monday in the Karachi Company area, in the capital, Islamabad.

Police are attempting to trace a phone call, which they say Khan's assailants used to lure him to the area.

Khan was known to have close ties with hardliner Islamist groups. His Twitter account, which he used to regularly criticize Prime Minister Imran Khan and Pakistan's powerful security forces, had over 16,000 followers at the time of his death.