Seven land rights and religious freedom activists went on trial in Vietnam on Monday on subversion charges which US lawmakers decried as a "stain" on the country's rights record.

By Agence France-Presse,
Updated: 5/30/2011

Three of the accused, who are being tried by a court in southern Ben Tre province, are members of US-based opposition group Viet Tan, said the organisation, also known as the Vietnam Reform Party.

The defendants are all land rights activists and include a 52-year-old Mennonite pastor who is a veteran advocate on behalf of dispossessed farmers in the Mekong Delta, Viet Tan said. Two others are also Mennonite evangelists.

Most were arrested between July and November last year, Viet Tan said, adding that all are charged under Penal Code Article 79 based on their "affiliation" with the opposition group.

The charge of attempting to "overthrow the people's administration" is punishable by jail or a death sentence upon conviction.

Viet Tan calls itself non-violent and pro-democracy, but Vietnam -- a one-party communist state -- calls it a "terrorist group".

Land disputes and complaints that residents have been cheated out of compensation have become the most common cause of protests in Vietnam, a mainly rural country that is rapidly industrialising.

In a letter Thursday to Vietnamese Prime Minister Nguyen Tan Dung, five members of the US Congress described the case as "a stain on your government's increasingly troublesome religious freedom record".

The letter, led by Republican Representative Ed Royce, expressed hope that the charges against the "peaceful" activists would be dismissed.

Amnesty International has said dozens of peaceful political critics have been sentenced to long prison terms since Vietnam launched a crackdown on free expression in late 2009.

Vietnam says it has achieved significant progress on human rights.