A woman sentenced to death after being accused of converting from Islam to Christianity has been released from prison, according to her lawyer.

The case of Meriam Ibrahim, who is married to a Christian American, triggered an international outcry. She gave birth to a baby daughter, Maya, while in prison.

"Meriam was released just about an hour ago" Mohanad Mustafa told AFP.

Ms. Ibrahim (27) was convicted last month of apostasy and adultery and claimed she had always been a Christian, having been raised by her Ethiopian mother while her Muslim father had left when she was young.

She married Daniel Wani in 2011 and has refused to renounce her faith. But a court in Khartoum insisted she was a Muslim, and in Sudan such interfaith marriage is forbidden.

She was sentenced to 100 lashes for adultery and to hang for apostasy.

Her death sentence was suspended for two years so she could nurse Maya. Ms. Ibrahim also has a young son called Martin, who was also living in prison with her.

"The appeal court ordered the release of Meriam Yahya and the cancellation of the (previous) court ruling" Sudan's SUNA news agency said.

Mr. Mustafa said Ms. Ibrahim had been sent "to an unknown house to stay at for her protection and security. Her family had been threatened before and we are worried that someone might try to harm her" he said.

Earlier this month there was international condemnation of the mother's plight.

Sudan introduced Islamic Shariah law in the early 1980s under the rule of autocrat Jaafar Nimeiri, a move that contributed to the resumption of an insurgency in the mostly animist and Christian south of Sudan.

The south seceded in 2011 to become the world's newest nation, South Sudan.