A Pakistani judge has granted bail to a mentally disabled Christian girl accused of insulting Islam for burning pages of the religion's holy book.

Rights activists welcomed the decision Friday after calling for her release since she was arrested three weeks ago.

The case has focused attention on Pakistan's harsh blasphemy laws, which activists claim are used to persecute minorities and settle personal vendettas.

Judge Mohammed Azam Khan set bail at one million Pakistani rupees, or about $10,500, a significant sum in a country where many families live on only a few dollars a day. A Pakistani group that represents minorities said it would pay the bail.

"We feel that this is the real victory of truth and law," said Robinson Asghar, an aide to the Pakistani minister for national harmony who has been closely following the case.

A lawyer representing the girl, Tahir Naveed Chaudhry, said the bail would be paid Saturday, and then she would be freed. She is being held in a prison in Rawalpindi, a city next to the capital of Islamabad.

The young girl, who is reported to be 14 years old and suffering from some form of mental impairment, was arrested after an angry mob showed up at a police station in her neighbourhood in Islamabad and accused her of burning pages from the Qur'an, an act punishable by life in prison under the country's harsh blasphemy laws. Her lawyer has denied the allegation.

In an unusual twist, police arrested a Muslim cleric from her neighbourhood a week ago after a follower from his mosque accused him of stashing pages of a Qur'an in her bag to make it seem as if she burned them. He allegedly planted the evidence to push Christians out of the neighbourhood and is now being investigated for blasphemy himself. He has denied the allegation.

The judge gave no reason for granting bail. During the lengthy hearing in an Islamabad courtroom, attorneys for the young girl argued that the accusations against the cleric had raised reasonable doubt about her culpability in the case.

"No evidence has been brought up against her for wilfully committing this crime," said one of her lawyers, Pervez Khan.

Khan said people in the neighbourhood wanted to evict the Christians.

"To achieve this nefarious design, they have framed a minor girl in this case," he said.

Rao Abdur Raheem, a lawyer for the man who brought the complaint against the girl, said the judge felt she was better able to defend herself outside prison but cautioned that the case would continue.

"This doesn't mean the allegations against her were wrong," he said.

The Associated Press does not generally identify juveniles under 18 who are accused of crimes and is withholding her name.

While Friday's hearing was only to determine whether she deserves bail, the fact that the judge decided in her favour bodes well for her case.

Previous blasphemy cases have inspired widespread condemnation of the defendants by a Pakistani public that generally supports the laws. But few Muslim clerics or political leaders are pushing for her prosecution, likely due to the girl's age and mental state. In fact, a Pakistani association of Muslim clerics have been advocating on her behalf.

The head of Human Rights Watch in Pakistan, Ali Dayan Hasan, praised the judge's decision to grant the young girl bail.

"All charges against her should be dropped," Hasan said. "Human Rights Watch hopes that the blatant abuse that has come to light in this case will lead to a considered re-examination of the law, and all stake-holders in Pakistan will actively seek to end frequent abuses perpetrated under cover of blasphemy allegations."

Whether the case will lead to any changes in the blasphemy laws remains to be seen.

One of the key questions is whether she and her family will be safe once the girl is out from behind bars. People accused of blasphemy have often been victims of vigilante justice by angry mobs.

Last year two prominent politicians were gunned down in Pakistan for suggesting that the blasphemy laws should be amended so that they cannot be misused. The killer of one of the politicians was later lauded by supporters who threw rose petals whenever he appeared at court.

One of the girl's lawyers, speaking before the bail decision was announced, said it would be the responsibility of the government to protect her and her family if she's released but that he was confident they would be able to do it.

"We are really worried about her security," said Raja Ikram Ameen Minhas.