"Two groups of pastors were coming into Thailand to attend meetings. The first group made it over the Mekong River without any issues. The second group, however, was followed by the Laotian police," said Voice Of the Martyrs Canada (VOMC), an advocacy group investigating reports of persecution.

VOMC said the pastors were searched, and all of their belongings were confiscated from them, including a cell phone."

The pastors have reportedly been taken back to Laos March 18, but there has been no recent contact with them to confirm their whereabouts, the group added. VOMC said it had urged its supporters to "Pray that Laotian authorities will stop their campaign against Christians and come to know Christ as Lord."

CHRISTIAN FAMILIES

News of the latest arrests came shortly after at least 15 Christian families in Laos remained unaccounted for last month after security forces raided their villages and Hmomg church leaders were sentenced to 15 years imprisonment, human rights investigators said.

Rights groups say that although there has been economic progress, Communist authorities have been reluctant to allow more religious freedom as they view Christianity as Western and a threat to their powerbase and ideology.

In 1975, the Communist Pathet Lao took control of the government ending a six-century-old monarchy and instituting a strict socialist regime closely aligned to Vietnam.

A gradual return to private enterprise and the liberalization of foreign investment laws began in 1986 and Laos became a member of the geopolitical and economic organization Association of Southeast Asian Nations, or ASEAN, in 1997.