Cairo (CNN) -- Coptic Pope Shenouda III, the spiritual leader of Egypt's Coptic Christian community for nearly four decades, died Saturday, according to the head of the Egyptian General Coptic Association. He was 88.
"Shenouda III suffered renal failure ... due to the diabetes he endured for years," Sheif Doss told CNN.
The leader of the Coptic Christian community for 38 years, Shenouda was in poor health off and on for many years. He traveled to the United States to undergo medical tests last year.
Egypt's population is roughly 9% Coptic Christian, according to the U.S. State Department.
The Christian minority has been the target of a number of high-profile attacks in the past several years, including the bombing of a major church in Alexandria last January that left at least 21 people dead.
"The funeral is expected to take place in two days, as massive preparations must take place first. It is a historical event and 2 million people are expected to attend the prayers. I don't expect violence though," Doss said.
Markus Askuf, spokesman for the Coptic Church, said Shenouda's body is expected to arrive at the Coptic cathedral in Cairo at noon Sunday. Visitors will be permitted to come and pray there.
Shenouda will be buried Tuesday at Emba Bishoy monastery in Wadi Natroun, northwest of Egypt's capital, Askuf said. The area is home to some of the world's earliest Christian monasteries.
The Coptic Orthodox Church is the largest Christian church in the Middle East, according the Coptic Orthodox Church Centre in Stevenage, England.
In addition to millions of followers in Egypt, the church has adherents in Europe, Canada, the United States, Kenya, Zimbabwe, Namibia and South Africa, the center says.
U.S. President Barack Obama and his wife offered their condolences Saturday after news of Shenouda's death spread, saying he will be remembered as "a man of deep faith, a leader of a great faith, and an advocate for unity and reconciliation."
"His commitment to Egypt's national unity is also a testament to what can be accomplished when people of all religions and creeds work together," the Obamas said.
When a Coptic pope dies, all 150 bishops of the church's Holy Council appoint an acting patriarch until a vote is conducted for a successor, Doss said. Thousands of bishops, priests and monks are eligible to vote.
The most senior bishop usually takes the role of acting patriarch. In this case, that would be Bishop Michael of Asiut. If he declines, Bishop Bakhamious of Behira is next in line, Doss said.