Saudi Arabia, one of the United States’ key Arab allies, rounded up 28 Christians on Friday after receiving a tip about a home-based church. The Commission for the Promotion of Virtue and Prevention of Vice arrested the worshippers at a prayer meeting in the home of an Indian national in the city of Khafji. Their current whereabouts are unknown.

"Saudi Arabia is continuing the religious cleansing that has always been its official policy," Nina Shea, director of the Washington-based Hudson Institute’s Center for Religious Freedom, told FoxNews.com. "It is the only nation state in the world with the official policy of banning all churches. This is enforced even though there are over 2 million Christian foreign workers in that country. Those victimized are typically poor, from Asian and African countries with weak governments."

The Saudi media reported different compositions of the arrested Christians. Some reports said the Christians were men and women, while the Saudi Gazette wrote that children, as well as men and women, were detained. It was unclear if a court date has been set in the notoriously opaque fundamentalist court system. Saudi Arabia has gone to great lengths over the years to re-brand its image as a tolerant advocate of multi-religious dialogue. The arch-conservative monarchy funded the Vienna-based King Abdullah International Center for Interfaith and Intercultural Dialogue. Nevertheless, critics argue, Saudi Arabia’s Islamist religious police continue to expunge any trace of Christianity within its territory. Saudi Arabia’s King Abdullah appears to be tied up in knots because of his conflicting messages to the international community about religious diversity. "Such actions are especially dangerous in the current situation, where the world is seeing the rise of extreme Islamist groups in Iraq, Syria, Nigeria, Somalia and elsewhere," Shea said. "The West should demand that its strategic ally, Saudi Arabia, release the Christians at once and allow them to pray according to their own faith traditions. Otherwise, Riyadh will appear to be validating the practices of the Islamic State in northern Iraq and Syria.”

Rep. Frank Wolf (R-VA) pledged to press the State Department and the U.S. ambassador in Riyadh to help the Christians. Meanwhile, Secretary of State John Kerry is scheduled to visit the Kingdom tomorrow to discuss ISIS. Whether he will bring up the recent arrests remains to be seen.