A Pakistani court has sentenced to death a man who allegedly committed blasphemy on Facebook, a prosecutor said, in the first such case involving social media.

The conviction of Taimoor Raza, 30, came after a high-profile crackdown against blasphemy on social media by the government of Prime Minister Nawaz Sharif.

Blasphemy is a highly sensitive topic in Muslim-majority Pakistan, where insulting the Prophet Muhammad is a capital crime for which dozens are sitting on death row. Even mere accusations are enough to spark mass uproar and mob justice.

Shafiq Qureshi, public prosecutor in Bahawalpur, south of provincial capital Lahore, said Raza was convicted for allegedly making derogatory remarks against Prophet Muhammad, his wives and companions.

"An anti-terrorism court of Bahawalpur has awarded him the death sentence," Qureshi told Reuters news agency, adding: "It is the first-ever death sentence in a case that involves social media."

It is rare for a counterterrorism court to hear blasphemy cases but Raza's trial fell under this category because his charge sheet included counterterrorism offences linked to hate speech.

Qureshi said Raza was arrested after playing blasphemous and hate speech material on his phone at a bus stop in Bahawalpur, where a counterterrorism officer arrested him and confiscated his phone.

The material obtained from the phone led to Raza's conviction, he added.

"The trial was conducted in Bahawapur jail in tight security," Qureshi said.

Qureshi added that Raza belongs to the minority Shia community and in court he accused of spreading "hate speech" against the Deobandi sect, which adheres to a strict school of Sunni Islam.

Several other violent incidents linked to blasphemy accusations have alarmed human rights groups and activists in recent months.

Police are currently investigating over 20 students and some faculty members in connection with the killing of Mashal Khan, a student who was beaten to death on April following a dorm debate about religion - an attack that shocked the country.

Since then, parliament has discussed adding safeguards to the blasphemy laws, a move seen as groundbreaking in Pakistan where political leaders have been assassinated for even discussing changes.

As Raza's blasphemy conviction was under the counterterrorism court, he will be able to appeal his sentence in the High Court and later in the Supreme Court.

There have been at least 71 people murdered in connection with blasphemy allegations in Pakistan since 1990, according to an Al Jazeera tally.