US Congress members Chris Smith and Zoe Lofgren have nominated two Vietnamese church leaders for the 2013 Nobel Peace Prize.

Father Thadeus Nguyen Van Ly, 65, is a Catholic priest and prominent human rights activist.

He has campaigned for human rights and religious freedom since the seventies. He is also an outspoken advocate of democracy and the free press.

Father Ly has spent more than 15 years in prison for his beliefs. In 2007, he was sentenced to eight years in prison for "disseminating slanderous and libellous information" considered harmful to the state.

He was given just over a year of temporary medical parole due to ill health but was rearrested by the Vietnamese authorities in July 2011.

The United Nations Working Group on Arbitrary Detention highlighted his case in 2010 and said that Father Ly had been denied access to legal counsel.

Father Ly has been nominated alongside Buddhist monk and human rights activist, the Most Venerable Thich Quang Do.

Thich Quang Do is leader of the Unified Buddhist Church of Vietnam and was sentenced to five years in prison in 1995 for organising a humanitarian relief mission. He also spent 10 years in exile as a result of his outspoken views on human rights.

Despite suffering government persecution since 1975, leaders of the UBCV remain committed to speaking up for human rights.

Christian Solidarity Worldwide welcomed the nominations.

Advocacy director at CSW, Andrew Johnston, said: "In fighting for freedom and human rights, both men have had their own freedom curtailed and their rights restricted, yet they persevere.

"We hope that their nomination will focus international attention on the Government's treatment of religious and political dissidents.

"CSW joins Father Ly and the Most Venerable Thich Quang Do in calling on the Government of Vietnam to protect and promote human rights and religious freedom in Vietnam."

The winner of the Nobel Peace Prize will be announced in October.