"It's absolutely clear that Christians in Syria are being persecuted," the Archbishop of Canterbury said this week.
The Most Reverend Justin Welby was speaking at a fringe event hosted by Open Doors at the Church of England's General Synod in York.
Open Doors is running a 'Save Syria' campaign encouraging Christians to pray and petition their MPs on the situation in the conflict-torn country.
The Archbishop told of how in Aleppo, a historically Christian area since the first century, people "are being chased out in large numbers".
"I would encourage people to pray very strongly, continue to pray and to support this kind of campaign and to write to MPs asking them to think very carefully about the wisdom of supplying further weapons to an area of such complex and extreme violence," he said.
The call coincides with the release of an Open Doors report noting worrying reports of Christians being deliberately targeted in Syria.
The report detailed how Christians in one town were ordered through the local mosque loudspeakers to leave or else be slaughtered one by one.
Alistair Burt, Foreign Office Minister for the Middle East and North Africa, who was present at the launch said: "What the petition tells us is that not one side or the other should win, just that the killing has to stop for normal life to return and it is the biggest determination of the UK government to do all we can to assist that."
The Archbishop promised to speak out about the plight of Syrian Christians in meetings with government figures.
Open Doors Advocacy Director Stephen Rand said: "Open Doors is not campaigning solely for the Christian population. Our petition calls for action on behalf of all the people of Syria.
"But as a Christian organisation we are speaking out for the church to 'strengthen what remains' and honour those Christians who decided to stay and serve others in a dangerous situation.
"The church in Syria do not wish to be seen as victims and want to speak out for the whole of Syrian society. A future Syria must include all minorities, including Christians."