The US ambassador to Vietnam on Thursday called on the communist one-party state to free its dissidents and open up its political system, in an editorial the embassy sent to local media.

Ambassador Michael Marine said last week's eight-year jail sentence for activist priest Father Nguyen Van Ly was "baffling considering his crime was peacefully speaking out in favor of political change."

"Today, regrettably, there are an increasing number of individuals in prison or under detention in Vietnam whose only crime was the peaceful expression of their views," he wrote in a commentary sent to newspapers here.

He listed several other prominent dissidents currently being held -- journalist Nguyen Vu Binh, Hanoi human rights lawyers Nguyen Van Dai and Le Thi Cong Nhan, land rights activist Bui Kim Thanh and lawyer Le Quoc Quan.

"For the sake of Vietnam's further international integration and
development, its government must release these and other individuals
now," wrote Marine.

He also urged Vietnam to revise or repeal laws in order to legalise "the peaceful expression of one's views -- even if they are critical of the state."

Marine also praised Vietnam for its economic growth and recent accession to the World Trade Organisation.

But he said excitement about Vietnam's economic potential was being dampened by the "weak rule of law in Vietnam," lagging regulatory reforms, frail investor protection and "the cancer of widespread corruption."

"Vietnam aspires to greater international recognition, increased global integration and the achievement of world-class standards in everything from business to education, and health to economic infrastructure," Marine wrote.

"It is in Vietnam's own developmental and national security interests to ensure that its citizens also have world-class rights and freedoms."

He urged Vietnam to allow its citizens "greater space to express ideas" and "ultimately, the right to select their leaders and representatives."

The US envoy warned that Vietnam will not achieve its full potential "without strengthening (the) rule of law, tackling corruption, ensuring the basic rights and freedoms of its citizens and opening its political
system."

Vietnam Foreign Ministry spokesman Le Dung, in a regular press briefing, praised US-Vietnamese relations and said "we shouldn't make the differences in some areas influence or cause bad impacts" on overall bilateral ties.

He said that "in Vietnam no one is arrested or detained for expressing their political or religious views," speaking through an official translator.

"Dealing with Nguyen Van Ly and other wrongdoers is to ensure the rightness and correctness of the rule of state and to maximise democracy and protect the human rights and the discipline of Vietnam's laws," he said.

Dung added that Vietnam would send a delegation to Washington later this year to continue the bilateral human rights dialogue.