The European parliament has attacked what it describes as the repression of religious groups in Vietnam.
Religion in Vietnam is controlled by the state
The parliament accused the Communist authorities in Hanoi of adopting a "deliberate policy" of eliminating non-recognised churches.
It called for the release of dissident Buddhist leaders and others "detained because of their faith".
Vietnam has been under international scrutiny over its treatment of religious and political dissidents.
The European Parliament called for the release of Thich Huyen Quang, who heads the banned Unified Buddhist Church of Vietnam, and his deputy Thich Quang Do.
They have spent more than 20 years in prison or under house arrest since the Communist Party set up the state-approved Buddhist Church of Vietnam in 1981.
Both men were released from house arrest in July but are reported to have been re-arrested last month.
The parliament said a number of other independent religious groups were being targeted - including the Catholic Church, Montagnard Christians and Hoa Hoa Buddhists.
The resolution called on EU member states to coordinate efforts to promote religious freedom in Vietnam.
"Respect for human rights is one of the essential elements of the cooperation agreement signed between the European Union and Vietnam," the EU parliament said.
The United States Congress approved a similar resolution on Wednesday.