LAHORE (AFP) - A Pakistani anti-terrorism court on Monday remanded in custody four people accused of killing a Christian couple for alleged blasphemy, officials said.

Shehzad Masih, a bonded labourer, and his pregnant wife Shama Bibi were beaten by a mob of 1,500 people then thrown on top of a lit furnace last week in a crazed reaction to rumours they had thrown pages of the Quran into the garbage.

The horrific incident took place on November 4 in the tiny hamlet of Chak 59 (village 59) near the town of Kot Radha Kishan, 60km southwest of Lahore.

It has sparked protests across Pakistan by Christians and outrage among rights activists. Police have arrested more than 40 suspects.

"The police produced four suspects in anti-terrorism court and the judge remanded them into police custody for further interrogation till November 19," a prosecution official told AFP.

He said 39 more suspects were already in jail, out of a total of some 60 suspects named in the lynching of the Christian couple.

Some 900 students from Lahore's missionary schools staged a demonstration outside Lahore Press Club against the murders.

Protesters shouted "We want justice!" and "Stop killing minorities!" They carried placards and banners, including one which read "Death penalty for the killers of Shehzad and Shama."

Blasphemy is a hugely sensitive issue in the majority Muslim country, with even unproven allegations often prompting mob violence.

Those who take part in the violence are rarely if ever prosecuted - a fact not lost upon the relatives of the deceased.