At least 26 people were killed and 25 were wounded Friday in Egypt when gunmen attacked two buses and a truck full of Coptic Christians on their way to the Saint Samuel Monastery. Masked shooters wearing fatigues shot at the passengers from three four-wheel drive vehicles, according to Egypt’s Interior Ministry.

While no group had yet taken responsibility for the attack and the shooters had not been caught, Coptic Christians have routinely been the subject of persecution in Egypt. The religious minority makes up an estimated 10 percent of the country’s population and has been attacked in the past. When the shooting took place Friday, Egypt was still under a state of emergency after a pair of attacks on Coptic churches on Palm Sunday that killed at least 45.

Read: Who Is Hashem Abedi? Brother Of Manchester Attacker Arrested For ISIS Ties

Islamic State Group, also known as ISIS, vowed more attacks on the religious group in 2016 after they took responsibility for the bombing of a Coptic cathedral in Cairo that killed 25 people. At the time, ISIS vowed to increase its “war on polytheism,” a reference to Christianity, according to the New York Times.

RTX37RDN
A photo shows the aftermath of an attack on buses carrying Coptic Christians in Minya Province, Egypt, May 26, 2017. Egypt TV/Reuters

“It is very possible that this is part of that campaign,” Timothy Kaldas of the Tahrir Institute for Middle East Policy told Al Jazeera Friday. “[ISIS] has a great deal of sectarianism in their ideology and have targeted people based on their faith.” Kaldas noted it was very likely that the attack was carried out by ISIS.

Coptic Christians, whose theology is grounded in the teachings of the apostle Mark, separated from Christianity as a whole after a theological dispute. In the years since Hosni Mubarak’s regime was ousted in 2011, Coptic Christians have been on the receiving end of ever-increasing violence and persecution. Members of the religious group are routinely excluded from important positions of government and security services and have been leaving some Egyptian towns in mass numbers in recent years as a result of violence.

“Even at the height of Egypt’s experiment with liberalism from 1923 to 1952, a Copt could never escape his Coptic identity, nor, paradoxically, bring it to the public square,” the Atlantic reported in 2016. “Despite proclamations of equality by the state, a Copt has never been an equal Egyptian citizen in the eyes of the law. Egyptian laws are, in fact, designed to remind him of his second-class nature.”

Read: UK National Terror Threat Raised To Highest Possible Level After Manchester Attack

In a report issued by Amnesty International in March, the humanitarian group urged authorities to offer protection to Coptic Christians as soon as possible.

“This terrifying wave of attacks has seen Coptic Christians in North Sinai hunted down and murdered by armed groups,” Naija Bounaim, deputy director for Campaigns at Amnesty International’s Tunis office, said in the report. “No one should face discrimination – let alone violent and deadly attacks – because of their religious beliefs.”

RTX37RDJ
A photo shows the aftermath of an attack on buses carrying Coptic Christians in Minya Province, Egypt, May 26, 2017. Egypt TV/Reuters