KHARTOUM, Sudan -- A Christian woman sentenced to death in Sudan and later freed has been detained at an airport while trying to leave the country Tuesday, her lawyer said.

Lawyer Eman Abdul-Rahim told The Associated Press that the 27-year-old Meriam Ibrahim was held along with two children and her husband at the international airport in Khartoum, the country's capital. Abdul-Rahim did not elaborate and security officials did not respond to requests for comment.

U.S. State Department spokeswoman Marie Harf told reporters in Washington that the Sudanese government had informed American officials at the embassy in Khartoum that Ibrahim and her family were "temporarily detained" over issues relating their travel documents.

Harf said the Sudanese have assured the U.S. that the family is not under arrest and that they are safe. She said U.S. officials are continuing to work on getting them out of the country.

Ibrahim, whose father was Muslim but who was raised by her Christian mother, was convicted of apostasy for marrying a Christian. Sudan's penal code forbids Muslims from converting to other religions, a crime punishable by death.

Ibrahim married a Christian man from southern Sudan in a church ceremony in 2011. As in many Muslim nations, Muslim women in Sudan are prohibited from marrying non-Muslims, though Muslim men can marry outside their faith. By law, children must follow their father's religion.

The sentence drew international condemnation, with Amnesty International calling it "abhorrent." The U.S. State Department said it was "deeply disturbed" by the sentence and called on the Sudanese government to respect religious freedoms.

On Monday, Sudan's Court of Cassation threw out Ibrahim's death sentence and freed her after a presentation by her legal team.

Sudan introduced Islamic Shariah law in the early 1980s under the rule of autocrat Jaafar Nimeiri, contributing 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.

Sudanese President Omar Bashir, an Islamist who seized power in a 1989 military coup, has said his country will implement Islam more strictly now that the non-Muslim south is gone.

A number of Sudanese have been convicted of apostasy in recent years, but they all escaped execution by recanting their new faith.