The Archbishop of Canterbury has warned that there are forces at work that have turned the Arab Spring into a ''very anxious time''' for Christians.
Dr Rowan Williams told the BBC that the vacuum left by the end of autocratic regimes was being filled by extremists.
He said there have been more killings of Christians and burnings of churches in Egypt than people were aware of.
In an interview on The World at One, Dr Williams said he was ''guardedly optimistic'' that the political upheavals in the Middle East and North Africa would bring greater democracy to the region.
''In the long term, of course, a real participatory democracy in the region is bound to be in the interests of minorities because good democracies look after minorities,'' he said.
But in the short term, he warned, people were using the chaos it had brought to attack Christian minorities.
''There is no doubt at all that it is a very anxious time for Christian communities. There have been extremist atrocities already, especially in Egypt,'' he said.
''It is a fairly consistent pattern over a number of months.''
Dr Williams said violent extremism had made life unsustainable for Christians in northern Iraq, in a way that amounted to ethnic cleansing.
"The level of violence has been extreme," he said.
He said that even in Syria, where Christians and Muslims had long lived together peacefully, tensions were building to breaking point.