Persecution watchdogs sounded the alarm this week after learning that authorities in predominantly Muslim Algeria have closed half the Protestant churches in the country over the last six months.

Twenty-six Algerian churches were shut down either by official written order or verbal warning since November 2007, according to Open Doors USA. The churches, ranging in size from several dozens to more than 1,000 members, are victims of a recent aggressive campaign against Christians.

It is feared that if persecution continues all the churches will be closed by the end of the year.

"This was actually caused by an ordinance that was passed in 2006," said Open Doors' Advocacy Coordinator Lindsay Vessey to Mission Network News. "This ordinance, basically, was making it more difficult for churches to worship. It restricts where they can worship and also tries to prevent Christians from proselytizing or evangelising."

In March 2006, Algeria passed a law that required non-Muslim places of worship to have a government-issued certificate proving that they adhere to state worship guidelines. But Christian groups have accused the government of using various means to block their registration process, and complained that the regulations are unclear.

According to Compass Direct, the law restricting non-Muslim worship did not take effect until this year.

In addition to church closures, the crackdown on Christians also includes the arrest of Protestants as they travel between cities or exit religious meetings, and blocking Catholics from participating in regular ministry activities taking place outside of their church buildings.

Last month, an Algerian Christian was detained five days, fined $460, and given a one-year suspended prison sentence for carrying a Bible and personal Bible study books, according to Compass. The young Christian man was a convert from Islam and had reportedly told fellow believers that police pressured him to return to Islam while he was in custody.

Several other reports in May revealed that Christian converts were being pressured to return to Islam, and harassed for practising their new faith without a licence.

Experts and Algerian Christians say the recent crackdown is down to increased anti-Christian propaganda in Arab media and that it is a ploy to distract Algerians from pressing domestic concerns such as national housing shortage and inflation of staple goods prices. They also believe it can be attributed to a growing number of Christian converts from Islam, according to Compass.

Algeria has 32 congregations that belong to the Protestant Church of Algeria, and another 20 small fellowships that exist independently. There are at least 10,000 Protestants in Algeria.

Islam is the official state religion of Algeria, where 99 per cent of its 33 million population is Muslim.

Open Doors has launched a worldwide advocacy campaign calling on concerned Christians to contact their local Algerian Embassy to ask that the Algerian Government stop church closures and reopen those that have already been closed.

"We need to tell the Algerian Government that these church closures must stop, and that freedom for all religions must be respected," says Open Doors USA Advocacy Programme Manager Lindsay Vessey. "Also, keep Algerian believers in your prayers."