Knots of protesters from an ultra-Islamist party blocked roughly 10 key roads in the southern city of Karachi and others in eastern Lahore, Geo TV and other channels said. Private schools in both cites were shut, as well as in the capital.

Groups of about 200 protesters from the Tehreek-e-Labaik (TLP) party sat under large tents, listening to speeches on two blocked roads in Karachi, a Reuters witness said.

In one speech, a TLP speaker exhorted supporters to light new fires if the police managed to douse burning tires and other objects they had already set ablaze.

The demonstrators were protesting against the court’s decision to free Asia Bibi, a mother of four, who had been living on death row since 2010, as the first woman sentenced to death by hanging under Pakistan’s tough blasphemy laws.

Bibi was accused of making derogatory remarks about Islam after neighbors objected to her drinking water from their glass because she was not Muslim.

But a three-judge panel set up to hear the appeal, headed by Chief Justice Saqib Nisar, ruled the evidence was insufficient.

The case has divided Pakistan, where two politicians who sought to help Bibi were assassinated, and outraged Christians worldwide, with Pope Francis saying he personally prayed for Bibi.

In a televised national broadcast late on Wednesday, Prime Minister Imran Khan warned the protesters the government would act against any prolonged blockade.

“We will not allow any damages. We will not allow traffic to be blocked,” Khan said. “I appeal to you, do not push the state to the extent that it is forced to take action.”

Khan’s broadcast followed comments by a senior leader of the Islamist TLP group, calling for Chief Justice Nisar and the other two judges to be killed.

“They all three deserve to be killed,” TLP co-founder Muhammad Afzal Qadri told a protest in Lahore. “Either their security, their driver, or their cook should kill them.”

He also called for the ouster of Khan’s new government and urged army officers to rise up against powerful military chief General Qamar Javed Bajwa.

Hafiz Saeed, an influential Islamist whom the U.S. accuses of being the mastermind of attacks in Mumbai in 2008 that killed 166, has called for protests after Friday afternoon prayers.

Another Islamist group, the Milli Yakjehti Council, is also meeting on Thursday to discuss Bibi’s case and may launch protests.

The whereabouts of Bibi and her family are unclear, and speculation is growing that she will leave Pakistan with her family, who have been in hiding for much of the past eight years.