CAIRO -- Dozens of Coptic Christians were tortured inside a detention center run by a powerful militia in eastern Libya, two of the recently released detainees told The Associated Press on Friday amid a wave of assaults targeting Christians in Benghazi and the latest instance of alleged abuse by Libyan security forces.

The two, among an estimated 50 Egyptian Christians who have been detained in Libya on suspicion of proselytizing, told of being rounded up in a market by gunmen who checked their right wrists for tattoos of crosses.

"They first checked our wrists searching for the crosses and if they found them, we [had to] get into their cars," said 26-year-old Amgad Zaki from the southern city of Samalout in Minya province, 135 miles south of Cairo.

Zaki said a group of men -- some in uniform and some in civilian clothes -- rounded up Egyptians selling clothes in a market called el-Jareed in Benghazi on Feb. 26. He and other Christians climbed into SUVs that he said carried the sign of Libya Shield One, one of the most powerful militias in Benghazi that is under the command of Islamist and ex-rebel Wassam Bin Hemad.

"They shaved our heads. They threatened to sever our heads in implementation of Islamic Shariah [law] while showing us swords," said Zaki, who was interviewed on the telephone from his home after returning to Egypt earlier this month.

"They dealt with us in a very brutal way, including forcing us to insult our Pope Shenouda," Zaki said, referring to the former Coptic pontiff who died last year.

He said that during four days of detention they were flogged, forced to take off their clothes in cold weather and stand at 3 a.m. outdoors on floor covered with stones.

"I was taken to clean a bathroom, and the man pushed my head inside the toilet and sat on me," he said. "I was dying every day, and at one point I thought death is better than this."

Militias have been targeting Christians, women, journalists, refugees and those considered former loyalists of Moammar Gadhafi, who was toppled and killed in Libya's 2011 civil war. The state relies on the militias to serve as security forces because Libya's police and military remain in shambles.

Egypt's foreign ministry said that its embassy in Libya was investigating the allegations of torture.

The militia that held the group claimed it treated the Coptic Christian detainees well.

However, Atef Habib, a 34-year-old vendor who is also from Minya province, also alleged mistreatment in the detention center.

He recalled how a Coptic Christian priest was beaten up and his head and mustache were shaved by the captors. Habib said that an aide to the priest also was beaten. "His face was blackened and bleeding from beating," Habib said.

Fathi Ubaidi, one of the top commanders of Libya Shield, denied abusing the Coptic Christians. He said in a phone interview that the Egyptians were treated "very well" and "if there is any rights organization who would like to talk to them, they are more than welcome."

The family of one Coptic Christian who also was arrested in Benghazi for allegedly spreading Christianity said he was tortured to death in a detention center in the Libyan capital, Tripoli. His wife, Ragaa Abdallah, and his relatives blame his death on torture, but the Egyptian Foreign Ministry said that the man, Ezzat Atallah, who suffered from diabetes and a heart ailment, likely died of natural causes.

Earlier last week in Cairo, demonstrators burned a flag belonging to the Libyan Embassy to protest Atallah's death.

Hundreds of thousands of Egyptians are working construction and trade jobs in Libya, a nation of 6.5 Muslims with no significant religious minority. Hundreds are believed to have been killed in crossfire during the war and many others have lost their jobs.

Benghazi witnessed a series of assassinations of top security and military officials and diplomats' convoys have come under fire, prompting Western countries to urge their citizens to leave. On Sept. 11, U.S. Ambassador to Libya Chris Stevens was killed along with three other Americans during an assault on the U.S. mission in Benghazi. An Islamic militia group named Ansar al-Shariah was blamed for the attack.

The first word that dozens of Egyptian Christians had been detained spread after a video clip surfaced last month showing a Libyan militiaman in uniform holding a group of Christian Egyptians. The militiaman said that the detainees, whose heads were shaved, were among nearly 100 Coptic Egyptians being held for allegedly spreading Christianity in Libya.

The video showed Bibles and Christian books next to the detainees. It surfaced only a few days after authorities announced the arrest of an Egyptian, South Korean, South African and Swede, who had an American passport, for allegedly spreading Christianity. The Libyan police chief behind that case, Abdel-Salam el-Barghathi, said that the two cases are separate.

The story of the Coptic Christian detainees comes at the same time that the Libyan parliament has halted its sessions after being attacked by militiamen. The head of the parliament escaped an assassination attempt during last week's attack.

Moreover, two days ago, Hassan al-Amin, the head of the human rights committee of the parliament, fled to London in self-exile after receiving death threats to him and his family.

He told a private-owned Libyan network Al-Assima -- which was raided by unidentified gunmen more than a week ago -- that he was resigning from parliament. Al-Amin is a longtime opposition figure who has been on the run from Gadhafi's regime for nearly 30 years. His resignation came after speaking against militias and warning of their human rights abuses.

In an audio clip that was widely circulated on social media, al-Amin said he had seen abuses taking place in prisons that are "much worse than those that took place in the days of Gadhafi."