Hundreds of Muslim men set fire to churches and vandalised Christian homes during a rampage in eastern Pakistan on Wednesday, officials said, after Christians were accused of blasphemy.

The mob made its way through a predominantly Christian area on the outskirts of the industrial city of Faisalabad after allegations spread that the Koran had been desecrated.

"The crowd inflicted heavy damage on the area including to homes of Christians, and many churches," Ahad Noor, a district government official, told AFP.

Police and rescue officials said at least four churches had been set on fire, while residents said as many as a dozen buildings with church status had been damaged. 

Several thousand police have been sent to secure the area and dozens of people detained, Amir Mir, the information minister for Punjab province, said in a statement that also condemned the alleged blasphemy. 

Yasir Bhatti, a 31-year-old Christian, fled his home in a narrow alley next to one of the churches that was ransacked by the mob. 

"They broke the windows, doors and took out fridges, sofas, chairs and other household items to pile them up in front of the Church to be burnt. They also burnt and desecrated Bibles, they were ruthless," he told AFP by phone. 

Blasphemy is a sensitive issue in Muslim-majority Pakistan, where anyone deemed to have insulted Islam or Islamic figures can face the death penalty.

Pakistani bishop Azad Marshall, in the neighbouring city of Lahore, said the Christian community was "deeply pained and distressed" by the events.

"We cry out for justice and action from law enforcement and those who dispense justice and the safety of all citizens to intervene immediately and assure us that our lives are valuable in our own homeland," he posted on X, formerly known as Twitter.

- 'Failure to protect minorities' -

Images on social media showed crowds of people armed with sticks and rocks storming through the streets, with smoke rising from church buildings.

In one video, crowds cheer and demand punishment for the accused blasphemers as a cross is torn from the top of a church.

The boundary walls of a Christian cemetery were vandalised, as well as the local government office, police said.

Local Muslim leaders used mosque loudspeakers to urge their followers to demonstrate, according to videos posted on social media.

"Christians have desecrated the Holy Koran. All the clerics, all the Muslims should unite and gather in front of the mosque. Better to die if you don't care about Islam," one cleric is heard saying.

A police report said charges would be filed against two Christian men who have fled the area.

Christians, who make up around two percent of the population, occupy one of the lowest rungs in Pakistani society and are frequently targeted with spurious and unfounded blasphemy allegations that can be used to settle personal vendettas. 

Islamist right-wing leaders and political parties across Pakistan frequently rally around the issue. Politicians have been assassinated, European countries threatened with nuclear annihilation and students have been lynched over accusations of blasphemy.

"The frequency and scale of such attacks -- which are systematic, violent and often uncontainable -- appear to have increased in recent years," the Human Rights Commission of Pakistan said on Wednesday. 

"Not only has the state failed to protect its religious minorities, but it has also allowed the far right to permeate and fester within society and politics."

Washington on Wednesday voiced alarm at the attacks and urged Pakistan to launch an investigation.

State Department spokesman Vedant Patel said that while the United States backed free expression, "violence or the threat of violence is never an acceptable form of expression."

Christian woman Asia Bibi was at the centre of a decade-long blasphemy row in Pakistan, which eventually saw her death sentence overturned and she was later allowed to leave the country. 

Her case sparked violent demonstrations and high-profile assassinations while spotlighting religious extremism across wide sections of Pakistani society. 

Pakistan's newly appointed caretaker Prime Minister Anwaar-ul-Haq Kakar said on X that he was "gutted" by what was happening: "Stern action would be taken against those who violate law and target minorities."

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