The Vietnamese government has increased its persecution of Christians, according to a recent Human Rights Watch report.
The group accuses Vietnam of persecuting Christians and forcing them to renounce their faith.
"Freedom of religion does not mean freedom for state-sanctioned religions only," said Phil Robertson, the deputy Asia director of Human Rights Watch.
Human Rights Watch is calling on the U.S. State Department to put Vietnam back on the list of the world's worst religious rights violators. The country was removed from the list in 2006.
All religious groups in Vietnam are required to register with the government.
Vietnam's indigenous Christian community, known as the Montagnards, worship in unregistered house churches.
Human Rights Watch said the Vietnamese government is cracking down on the group for participating in religious activity that is not government controlled.