MINYA, Egypt (Reuters) - Last Wednesday, Ayub Youssef was driving to the southern Egyptian town of Delja where he works as a Catholic priest when a friend called and told him to turn back.

By the time he reached the town on Sunday, about 20 houses had been burned. An ancient monastery was smashed and ransacked. One of his parishioners, a 60-year-old barber named Iskander Tous, had been killed in the chaos.

Now, Youssef said, Christians in Delja were living like prisoners in their homes. "No one goes out at all. Not to buy food, not to get medicine, not for anything," he said.

Egypt's Coptic Christians, who make up 10 percent of its 85 million people, have coexisted with the majority Sunni Muslims for centuries. Violence erupted periodically, especially in the impoverished south, but the attacks on churches and Christian properties in the last week are the worst in years.

Some 20 churches have been attacked just in the Minya province where Delja is located, many burned completely. Across the country, mobs have killed several Christians and sacked scores of shops, homes, schools and monasteries.

The immediate trigger was a bloody crackdown in Cairo last Wednesday when police dispersed two Muslim Brotherhood sit-ins set up to demand the reinstatement of President Mohamed Mursi, deposed by the army on July 3 after mass protests against him.

Using snipers and armoured vehicles, police killed hundreds of protesters, prompting some hardline Brotherhood supporters to frame the bloodshed as part of a war against Islam abetted by Egypt's Christians. Forty-three police also died in the clashes.

The Brotherhood says it has nothing to do with the attacks on Christians, and accuses the army of cynically using them to justify an ever more brutal crackdown. Brotherhood spokesman Ahmed Aref said in a statement security forces had abandoned the churches to the attacks, which he blamed on "foolish boys."

Such arguments cut little ice with Egypt's Copts, who encompass the majority Orthodox as well as Catholics and Protestants; some of their leaders have now sided firmly with the military in saying the army crackdown is on "terrorism".

Copts now darkly evoke the memory of an Islamist insurgency that killed hundreds of people in the 1990s, many in southern Egypt, which has a high concentration of Copts and has long been a stronghold for militant Islamist movements.

"COPTS ALWAYS PAY THE BILL"

All four walls of the Evangelical church in Mallawi, south of Minya city, were still smouldering on Saturday, a day after assailants set it on fire with petrol bombs and gas canisters.

The roof had collapsed, and bits of twisted, charred metal lay among piles of carbonised wood and stones. Young men poured water on the ashes and stacked bricks in the arched windows to guard against more attacks. The smell of smoke hung in the air. Cinders and broken tiles crunched underfoot.

One young man held up a handful of bullet casings, one from birdshot, others apparently from assault rifles. Firing crackled from across town, where gunmen had attacked the police station three times since Wednesday, killing at least two policemen.

"It's becoming something like a war," said Rimon el-Rawy, a local journalist following the attacks.

Bishop-General Macarius, a Coptic Orthodox leader in Minya, recited attacks on local churches going back decades - one, Anba Antonios, was struck as early as 1979, he said; gunmen killed worshippers at another in the early 90s.

"Copts always pay the bill - in the days of Gamal Abdel Nasser, the days of Sadat, the days of Mubarak, the days of military rule, the days of Mursi and after Mursi," he said, listing rulers since Nasser's 1952 coup overthrew the monarchy.

Many Christians, who kept a low profile during decades of military-backed rule in Egypt, were unnerved by Mursi and his Islamist Muslim Brotherhood during their time in power.

Hardline Muslim clerics gained unprecedented freedom to preach on Egyptian television after the 2011 revolt that overthrew Hosni Mubarak and paved the way for Mursi's election, and some openly derided Christians on air.

Mursi also revived memories of the 1990s by allying with Gamaa Islamiya, a group at the heart of the insurgency which carried out attacks on Christians and tourists in southern Egypt but later renounced violence and entered mainstream politics.

Coptic Pope Tawadros II gave his public backing to Mursi's removal, sitting with liberal politicians and Muslim clerics beside armed forces chief Abdel Fattah al-Sisi when he announced the army intervention.

His support came even though at least 25 people had died when troops broke up a protest staged by Copts under the military rule that preceded Mursi's presidency.

Macarius said it was the same problems faced by other Egyptians - the failing economy, the Brotherhood's apparent eagerness to monopolise power - that had pushed many Christians to join demonstrations calling for Mursi to step down.

"When we went out to the protests, we went out as Egyptians, not as Copts. We came out carrying flags, not crosses," he said.

LIKE A WAR

Violence began in Minya even as Egyptians elsewhere were celebrating Mursi's removal, but it escalated sharply last week.

A Catholic church near the burned Evangelical church in Mallawi was also sacked and looted. Light leaking in from high windows illuminated charred paintings of saints, broken pews and a decapitated statue of the Virgin Mary.

Martin Wagih, a 32-year-old worker in a photography studio who lives across the street, said he had seen four bearded men in long robes drive up on motorcycles and fire at the church with automatic rifles and throw petrol bombs before a mob stormed it on Friday night.

"We don't know what to do now," he said. "We don't have any weapons. If we had weapons, we would deal with this."

Similar scenes have played out across the province.

In Minya city, about 270 kilometers (170 miles) south of Cairo, the fire lit by attackers at the Anba Moussa church was so intense that nearly everything inside has been reduced to white and black charcoal.

Attackers also burned a Christian-run orphanage. A local doctor pointed out red and black X marks spray-painted on shop doors in the same street. They were put there by Islamists to tell between Christian and Muslim shops, he told Reuters.

The doctor, who did not want to be named for fear of reprisals, later showed damage to his clinic, which Mursi supporters had pelted with bricks last week. One shattered the window and dented a wall near a clock with an image of Jesus.

"They're terrorists," the doctor said, gripping the brick that he had kept, his voice quivering with rage.

It is not always clear who is behind the assaults, but many in Minya, like Wagih, described attacks by smaller groups of Islamists followed by mobs of several hundred, including Mursi supporters and criminals taking advantage of the chaos.

"THEY MAY KILL US AT ANY MOMENT"

Blame for the attacks has become another element in the warring narratives offered by the military-backed government and the Brotherhood since Mursi's overthrow.

Authorities have portrayed them as part of a terrorist campaign unleashed by the Brotherhood, a charge echoed even more vehemently by private television channels and newspapers.

The Coptic Orthodox Church said in a statement it stood with the army and security forces in their confrontation with "armed violence and black terrorism".

Many cite speeches like one by Islamic cleric Safwat Hegazy at a Brotherhood rally in which he said most anti-Mursi protesters were Christians. He threatened the church if it backed the president's foes, drawing chants from the crowd of "With our blood and souls, we will sacrifice for you, Islam."

Yet Christians under attack have had little, if any, help from the state's emergency and security services. Helmy, the pharmacist in Mallawi, said fearful police and fire fighters had refused to come when the Evangelical church was burned.

"The situation was awful," he said. "There was no response from the police, nothing from the army, and nothing from the fire brigade."

Youssef, the Catholic priest, recalled a similar lack of response when his apartment in Delja was burned last month. There were still no police or army in the town by Tuesday, he said, despite weeks of attacks and violent rhetoric from Islamists.

"We're expecting that they may kill us at any moment."

(Reporting by Alexander Dziadosz; Editing by Alistair Lyon and Philippa Fletcher)