Aasia Bibi was convicted of blasphemy in 2009 after a quarrel with a fellow farmworker. The Supreme Court overturned her conviction last year, and she had been in protective custody since then.
Islamic extremists have rioted over the case and threatened to kill her. The same radical Islamists, many of whom have been jailed for their threats, also urged the overthrow of the government following Bibi's acquittal.
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Wilson Chawdhry of the British Pakistani Christian Association told The Associated Press that he received a text message from a British diplomat saying "Aasia is out." A close friend of Bibi also confirmed that she had left the country, speaking on condition of anonymity for fear of reprisals. Bibi's lawyer, Saif-ul Malook, said she had already arrived in Canada.
Officials at Pakistan's interior and foreign ministries also confirmed her departure, speaking on condition of anonymity because they were not authorized to brief media.
The case has brought international attention to Pakistan's controversial blasphemy law, which carries an automatic death penalty. The mere suspicion of blasphemy against Islam is enough to ignite mob lynchings in the country. The accusation of blasphemy has also been used to intimidate religious minorities and to settle scores.
Radical Islamists have made the punishment of blasphemy a major rallying cry, bringing tens of thousands into the streets and paralyzing major cities.
Salman Taseer, the governor of Punjab province, was shot and killed by one of his guards in 2011 for defending Bibi and criticizing the misuse of the blasphemy law. The assassin, Mumtaz Qadri, has been celebrated as a martyr by hard-liners since he was hanged for the killing, with millions visiting a shrine set up for him near Islamabad. Pakistan's minister for minorities, Shahbaz Bhatti, was assassinated later that year after demanding justice for Bibi.
Prime Minister Imran Khan has vowed not to be intimidated by the rioters, saying the rule of law would decide Bibi's fate.
But she was denied permission to leave the country for several months until sentiments cooled.