A London-based priest who is in Syria said that "fear is very high" in the nation.
The Rev Nadim Nassar, who in his home city Latakia, said it feels at times "like the whole city has closed down because people are scared to leave their homes".
Speaking on BBC Radio 4’s Today programme, Rev Nassar added: “On Sunday, you could hear a lot of shooting and bombing from different parts of the city.
“The whole city is now shut. The fear is very high, and people don’t know what’s going on and what is next.”
At least 30 people are reported to have been killed in Latakia so far, and government forces are accused of shooting at women and children trying to escape.
Tanks have gathered on the outskirts of the city.
Syrian government television has denied that any civilians have been targeted, and authorites says that it is tackling armed terrorist gangs.
The crackdown began last Saturday, a day after there were anti-government protests in the city.
The next day, activists say, Syrian warships fired shells at the city.
The activists say that the rebel movement has not resorted to violence, and that several government soldiers have switched allegiances.
Mr Nassar is the director of the Awareness Foundation, a charity that seeks to help Christians “make sense of their faith and culture in the 21st century, and to increase their awareness of their neighbours’ faiths and cultures”.
He is due back to preach at an Awareness Sunday service at Westminster Abbey, which will commemorate the tenth anniversary of 9/11,
Canon Jim Rosenthal, communications director of the Awareness Foundation, said: “He has spoken of feeling almost imprisoned in his house.
There is also a considerable lack of electricity.
"Naturally, we are deeply concerned for his family and are all praying he and his sister Huda will return safe and well."