A persecution charity has warned that Meriam Ibrahim is "still at risk from vigilantes", despite being released from prison yesterday.

Sudanese Christian Ibrahim was sentenced to 100 lashes and death by hanging on May 11. Thought she was bought up as a Christian, she was found guilty of converting from Islam and was also accused of adultery after marrying a Christian man.

She gave birth to a daughter, Maya, in prison, and was reportedly visited by an Islamic scholar who "read to her continuously from the Qur'an in order to help her 'return' to the Islamic faith", Christian Solidarity Worldwide (CSW) reports. However, she remained steadfast and refused to renounce her Christian beliefs.

Her shock release from prison yesterday was welcomed by campaigners all over the world, including Release International, but the charity has now warned that religious persecution is "worsening" in Sudan, and that Meriam may still be at risk from Islamic extremists.

Release notes concern for the Sudanese mother's safety, despite the court's declaration that Ibrahim is "innocent of all charges".

"We're delighted Meriam has been released, but it should never have come to this," says Release Chief Executive, Paul Robinson.

"Religious coercion - persecution by another name - is already getting worse for Christians in Sudan, despite the constitution. The authorities are becoming more rigid in their enforcement of Islamic law. They have demolished churches and deported Christians. And if it hadn't been for an international outcry, they might have taken the life of this woman."

Robinson continues: "The good news is that the appeal court has overturned the ruling. Release supporters were among those who pressed hard for this and we welcome that decision. The worry now is that militants who believe the courts have gone soft may try to take Meriam's life. It's already been reported that there have been death threats against her lawyers".

Release are thus urging the Sudanese government to increase protections for religious minorities across the country, in line with the constitutional commitment that states: "Every person shall have the right to freedom of creed and worship".

Under the law, religious coercion is also illegal, though Release notes that it is "a capital offence for a Muslim to change their faith," and Sudanese President Omar al-Bashir has called for the final draft of the constitution to be "100 per cent Islamic", which persecution advocates fear will put more pressure on members of minority faiths.

"We urge Sudan to continue to protect the religious freedom guaranteed under its interim constitution," Robinson concludes.

"Those guarantees must now be firmly enshrined in the forthcoming constitution and in law. And we call on the authorities to do all in their power to protect Meriam and her family."