Tens of thousands of supporters chanted and threw rose petals Tuesday at an ambulance bearing the body of a Pakistani Islamist executed for killing a liberal governor, as schools closed and police guarded flashpoints.
Crowds flooded into a park in the garrison city of Rawalpindi for funeral prayers for Mumtaz Qadri, chanting slogans such as "Qadri, your blood will bring revolution".
An AFP estimate put the number of people at up to 100,000.
Main junctions and sensitive buildings in Rawalpindi and the nearby capital Islamabad were guarded by thousands of police and paramilitary Rangers, while schools were shut.
Security forces kept a careful distance from the crowd at Liaqat Bagh park, and some of the supporters dispersed after the prayers.
But around 5,000 continued to march behind the flower-strewn ambulance as it inched its way through a sea of supporters towards the site where Qadri was buried Tuesday evening.
Qadri, a police bodyguard to Salman Taseer, shot the liberal Punjab governor 28 times at an Islamabad market in 2011.
He said he was angry at the politician's calls to reform the blasphemy law.
Blasphemy is a hugely sensitive issue in the Islamic republic, and Qadri, who was hanged early Monday, was hailed as a hero by many conservatives eager to drown out calls to soften the legislation.
Critics say the law -- which carries the death penalty -- is largely misused, with hundreds languishing in jails under false charges.
But those who lynch alleged blasphemers largely escape punishment.
Earlier, a few hundred Qadri supporters carrying sticks were seen among the crowd in Rawalpindi as they shouted slogans including: "The punishment for a blasphemer is beheading!"
- Key moment -
Analyst Amir Rana said Qadri's execution marked a key moment for Pakistan in its fight against religious extremism, which has lasted more than a decade.
"I think it is a very critical moment in the political history of Pakistan. It is the first time the political government has made such a decision (to carry out the execution)," Rana said.
"The resolve is on the rule of law and they will not allow space for extremism in Pakistan."
But Rana said the move might backfire by making Qadri a martyr.
Several supporters took turns to denounce and threaten the government before the funeral.
"The chief justice, the army chief and the president should fear the day when every single individual of the country will become Mumtaz Qadri and grab them on the streets of the country," said Khadim Hussain.
Mourners travelled from distant cities, including Karachi and Lahore as well as Pakistani-held Kashmir, while small demonstrations were held in cities such as Peshawar.
The media maintained a near-blackout on the news for the second day running, a move that analysts said has helped limit fallout from the execution.
A United Nations official said Tuesday all its staff had been sent home from various workplaces in the capital due to security fears, including from the tightly guarded diplomatic enclave.
Many schools and universities remained closed for the day after shutting early Monday.
Thousands had protested across Pakistan Monday after authorities announced the hanging had taken place early that morning.
But with security stepped up across the country of some 200 million, most dispersed peacefully.
Pakistan has never officially executed anyone for blasphemy. But anyone convicted, or even just accused, of insulting Islam risks a violent and bloody death at the hands of vigilantes.
Taseer had 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 Mohammed. Her case has been championed by the Pope.
On Tuesday some Qadri supporters attending funeral prayers chanted: "Death to Asia Bibi!".