LAHORE (AFP) - Thousands of angry protesters on Saturday set ablaze more than 100 houses of Pakistani Christians over a blasphemy row in the eastern city of Lahore, officials said.

Over 3,000 Muslim protesters turned violent over derogatory remarks against Prophet Mohammed allegedly made by a young Christian, Sawan Masih, 28, three days earlier, police official Multan Khan said.

The exact number of houses in Joseph Colony, a Christian neighbourhood in Badami Bagh area, were not immediately known but police and rescue officials said they belonged to low to middle-class families from the minority community.

"Police arrested Masih, a sanitary worker, on Friday night while the incident actually happened on Wednesday evening," Khan told AFP.

He said that the arrest was made when Masih's barber friend Shahid Imran complained that he had made blasphemous remarks about Prophet Mohammed, adding that Christians had fled the area on Friday evening, fearing a backlash.

Protesters began to assemble in the area on Saturday morning and later set fire to houses and other items including furniture, crockery, auto rickshaws, bicycles and motorbikes belonging to local Christians.

"Thick clouds of smoke engulfed the small houses, mostly consisting of one or two rooms, and many of them looked like charred shells," said an AFP reporter at the scene.

Police said protesters burnt 25 houses but Dr Ahmad Raza, in-charge of local rescue operations, and the independent Human Rights Commission of Pakistan (HRCP) put the number at more than 100.

Expressing grief and anger at the attack, HRCP chairwoman Zohra Yusuf put the number of houses burnt during the protest at over 100.

Police baton-charged the protesters to disperse them from the neighbourhood. There was no loss of life reported during the violence but 20 policemen were slightly injured during clashes, officials said.