The situation for Syria's Christians is worsening amid anti-regime protests, Open Doors USA has warned.

Despite international outcry over the brutality of the crackdown on the uprising, Syrian President Bashar al-Assad has ignored calls to step down.

In an interview with US TV channel ABC News this week, he denied issuing orders to kill his own people and questioned the credibility of the UN and its latest report putting the number of people killed since the outbreak of protests at 4,000.

Open Doors said Christians in the country are afraid of what might happen to them in the future, especially if radical Muslims gain power.

The organisation’s President, Dr Carl Moeller, fears Christians may soon have to think about leaving Syria.

"Christians inside Syria are caught in the crossfire as they are in many other Middle Eastern countries," he said.

"Until the protests started against the regime of President Bashar al-Assad, the Christian community enjoyed some protection. Now they are afraid of the future. Will they have to flee their country like Iraqi Christians have done over the last several years? Please lift them up in your prayers."

There are around 1.5 million Christians in Syria, including 100,000 Christian refugees who fled from Iraq because of violence and persecution there.

One Open Doors field worker, who cannot be named for security reasons, described a situation of increasing hardship for Syrians, with food levels down, fuel supplies running low, and daily electricity cuts.

The field worker reports that radical Muslims and criminals are “taking advantage” of the lawlessness.

"In the city of Homs, for example, the Sunni Muslims gained power on the streets when the government pulled out its troops for a few days.

“Some of the radical elements in this group have raided several churches. They robbed the churches of their most valuable things.”

Some Christians have already reported violent acts against them and fear they are a sign of more violence to come.

The field worker said that some radical Muslim taxi drivers have spoken of their intention to harm any woman using their taxi who is not veiled.

"These women, mostly less orthodox Muslims and Christians, are being kidnapped, raped or even killed," said the field worker.

"Some months ago two Christian women were kidnapped. One managed to jump out of the driving car, but the other was taken. That woman remains missing. This didn't happen in a remote area of the country but in the capital of Damascus. For women the situation is unsafe now. People still go on with their daily routine, but with more caution."