Pakistan on Monday hanged the assassin of a governor who sought reform of the country's blasphemy law, officials and supporters told AFP, saying Mumtaz Qadri - feted as a hero by Islamist supporters - had been executed at a prison in Rawalpindi.

"I can confirm that Qadri was hanged in Adialia jail early Monday morning," senior local police official Sajjid Gondal told AFP.

A prison official confirmed the execution of Qadri, a former police bodyguard who killed liberal Punjab governor Salman Taseer in 2011.

Around 50 Rangers and police in riot gear as well as ambulances and dozens of police vehicles were stationed outside Qadri's home in the city early Monday, an AFP reporter there said, blocking the street and refusing to allow people to enter.

Armed Rangers could be seen stationed on the roof of the building housing Qadri's residence and some roads in the neighbourhood were closed.

Cries were heard from inside the house as around 20 people gathered, apparently family members, and mosques could be heard broadcasting news of the execution.

Security stepped up

"We have beefed up security in Rawalpindi to maintain law and order and to deal with any untoward situation," Gondal said.

He said the hanging took place after a final meeting between Qadri and his family late on Sunday, and that the body had been sent to his relatives.

Qadri shot Taseer 28 times in broad daylight in an upscale market in the capital Islamabad.

He later admitted the killing, saying he objected to the politician's calls to reform Pakistan's controversial blasphemy laws.

Taseer had also been vocal in his support of Asia Bibi, a Christian woman who has been on death row since 2010 after being found guilty of insulting the Prophet.

Blasphemy is a hugely sensitive issue in Pakistan, an Islamic republic of some 200mn, and Qadri has been hailed as a hero by many conservatives eager to drown out any calls to soften the legislation.

Critics including European governments say Pakistan's blasphemy laws are largely misused, with hundreds of people languishing in jails under false charges.

Qadri's lawyers drew on Islamic texts to argue that he was justified in killing Taseer, saying that by criticising the law the politician was himself guilty of blasphemy - an argument rejected by the lead judge.

Qadri lost a petition for the Supreme Court to review his sentence in December last year.

The decision came after the court warned in October that in Islam a false accusation can be as serious as the blasphemy itself, and that calls for blasphemy law reform "ought not to be mistaken as a call for doing away with that law".

The court's decision to uphold the sentence sparked rallies in which Islamist groups said that if Qadri were executed those responsible should also be put to death.