(AFP) -- Dozens of Muslims gathered Thursday outside a Baghdad church where an Islamist assault killed 44 worshippers and two priests three years ago, appealing for Christians to stay in Iraq.

Full coverage of the Massacre of Assyrians At Our Lady of Deliverance Church in Baghdad.

Clergy led low-key prayers inside Our Lady of Salvation church in the capital's main commercial district of Karrada, on the anniversary of the October 31, 2010 attack. There was a heavy security presence outside, and people were barred from entering unless they could produce documents showing they were Christian. At the same time, journalists were not allowed to take photographs or film in the vicinity. "It is a wound that will never heal, and a crime that I will never forget," said Rafid, a Christian man who was walking to the church. "On this day, with all this pain, all I can think of is leaving the country, because the country is finished," said the 56-year-old carpenter, two of whose cousins were killed on that day. The attack, the single bloodiest one against Christians since the 2003 US-led invasion, shocked Iraq and the international community and sparked a massive flight of Iraqi Christians from the country. Another worshipper, a 37-year-old who gave his name as Abu Yaqub, or father of Yaqub, recalled the attack as a "terrifying day." "Their only sin is that they were praying," the accountant said, referring to the victims. "What had they done?" he continued. "How can we forget this day? We will never forget it. We will never forget it." Outside the church, both Sunni and Shiite Iraqi Muslims lit candles and held up banners appealing for their Christian countrymen to resist emigrating, and said they stood by the religious minority. Abbas Hassan, a retired civil servant, said "the Christians are the people of Iraq, for thousands of years, and Christianity is one of the oldest religions in Iraq." "We invite them not to leave Iraq, because all Iraqis share their pain." Another retiree, 65-year-old Faruq Baban, said: "I ask them not to emigrate, to hold their ground, because they are the people of Iraq, the original citizens." "It was an ugly crime that made me cry," he said of the attack, which was later claimed by an Al-Qaeda front group. "I suffered because they are my brethren, my fellow countrymen." Estimates of the number of Christians living in Iraq before 2003 vary from more than one million to around 1.5 million. But now they are estimated at fewer than 500,000. One of the oldest Christian communities in the world is the Chaldean church, which has 700,000 followers worldwide and uses Aramaic, the language that Jesus Christ spoke.