Christianity is in danger of extinction in some countries because of persecution of communities in areas of the world where they are a minority, a Government minister has warned.
Among the countries where Christians are being driven out are regions, such as Syria and Iraq, where the religion first took root, said Baroness Warsi, who has responsibility for faith communities.
She was using a speech at Georgetown University in Washington DC to raise her concerns and call on politicians in countries like Pakistan to "set the tone" for tolerance of religious minorities.
Lady Warsi told the BBC Radio 4 Today programme: "I'm concerned that the birthplace of Christianity, the parts of the world where Christianity first spread, is now seeing large sections of the Christian community leaving and those that are remaining feeling persecuted.
"There are huge advantages to having pluralistic societies - everything from the economy to the way people develop educationally, and therefore we all have an interest in making sure that Christian communities do continue to feel that they belong and are not persecuted in the places where this religion was born.
"One in 10 Christians live in a minority situation and large numbers of those who live in a minority situation around the world are persecuted."
In some cases, Christians are targeted for "collective punishment" by majority groups in retaliation for what they perceive as the injustices committed by Western powers, said Lady Warsi.
"Tragically, what's happening is they are being seen as newcomers, being portrayed as an 'other' within that society, even though they have existed there for many, many centuries," she said.
"What we are seeing, sadly, is a sense of collective punishment meted out by local groups - sometimes states, sometimes extremists. They are seen as legitimate targets for what they perceive as actions of their co-religionists. This concept of collective punishment and them being seen as agents of the West or agents of regimes is wrong. We need to speak out and raise this with the countries where this is happening."
The Foreign Office minister said she had already had "very frank conversations" with ministers in Pakistan, telling them that senior politicians have a "duty" to speak out against persecution and set a standard for tolerance. Some 83% of countries have constitutions guaranteeing freedom of religion, but do not implement these provisions, she said.
"There is much more that we can do," said Lady Warsi. "There's an international consensus, in the form of a Human Rights Council resolution on the treatment of minorities and tolerance towards other faiths. But we need to build political will behind that.
"Of course there have been moments when religious communities have been in conflict, but there have also been great moments of co-existence between faiths. There isn't an intrinsic clash between different faiths.
"Politicians need to set the standard. There was some interesting research in the US which said that the way in which a minority community is treated after an extremist incident is very much dependent on the tone that politicians set. Politicians do have a responsibility to set the tone, to mark out legal parameters as to what will and will not be tolerated."
Asked whether Lady Warsi's warning of the possible extinction of some Christian communities was correct, the leader of Catholics in England and Wales, Archbishop of Westminster Vincent Nichols, told Today: "I think in some parts of the Middle East that is probably true.
"There are real challenges for Christians in this part of the world to support and get alongside them and also for politicians to understand that the presence of Christians is a great mediating factor, often for example between different segments of Islam.
"It's a mix that has lasted for a thousand years and no Western government should promote a course of action in the Middle East which would end with a new government which was intolerant to its historical neighbours and colleagues within the territory."