Hue: Vietnam has released one of the country’s longest serving prisoners of conscience, ahead of US President Barack Obama’s visit to the nation.

Fr Nguyen Van Ly, who has spent much of the last two decades either in jail or under house arrest, was released on Friday, announced the Catholic archdiocese of the central city of Hue.

“Thadeus Nguyen Van Ly has returned to the mother diocese on Friday morning after his years and months in [northern] Nam Ha jail,” said the archdiocese’s short statement on its website.

The site also ran several photos of the ageing priest, dressed in a loose white shirt and baseball cap, being welcomed by church members.

Neither church nor government officials were immediately available for comment.

Father Ly, who is in his early 70s, is often compared to Myanmar’s Aung San Suu Kyi – both are veteran dissidents who have spent years in pursuit of greater democratic freedoms, reports the South China Morning Post.

But while Myanmar has recently emerged a nascent democracy, Vietnam remains a tightly controlled one-party state.

Fr Ly was jailed three times for a total of 14 years before his fourth and latest imprisonment in March 2007 when he was charged for spreading propaganda against the communist state.

He had been accused of helping to found “Bloc 8406,” considered one of the Vietnam’s first organized pro-democracy coalitions.

He gained prominence with his anti-government actions, including hunger strikes and several widely circulated missives calling for a multi-party system.

Fr Ly was briefly released from jail in March 2010 to seek treatment for a brain tumor and was placed under house arrest.

He was returned to jail more than a year later, sparking calls from the United States and international rights groups for his release.

Obama is scheduled to arrive in Hanoi early on Monday for a trip in which trade, security and human rights are expected to top the agenda between the two former enemies.

Speculation has swirled that the centerpiece of the visit could be the complete rollback of a decades-old US arms embargo on Vietnam.

Washington and Hanoi have grown close in recent years, partly through a joint desire to check Beijing’s saber rattling in the disputed South China Sea.

But rights activists fear this deepening closeness may prompt Washington to go easier on Vietnam over its dismal rights record.

Vietnam ruthlessly cracks down on protests, jails dissidents, bans trade unions and controls all domestic media.

Several political prisoners remain in jail, including Tran Huynh Duy Thuc, who is serving a 16-year sentence on charges of trying to overthrow the communist regime.

Online reports say he is planning a hunger strike in the next few days to protest his ongoing incarceration.

Meanwhile Obama spends his final year in office with foreign travels that some see as a global farewell tour.

He is on a weeklong trip to Asia as part of his effort to pay more attention to the region and boost economic and security cooperation.

He’ll spend three days in Vietnam, with stops in Hanoi and Ho Chi Minh City, formerly Saigon, for meetings with top leaders, a speech on US-Vietnam relations, visits to cultural treasures and sessions with civic leaders and entrepreneurs.

From Vietnam, he heads to Japan for a summit of the Group of Seven industrialized nations and a historic visit to Hiroshima.

Along the way, Obama will make a big push for the 12-nation trans-Pacific trade agreement, which includes the US, Vietnam and Japan. The deal is stalled in Congress, but Obama hopes it will one day increase trans-Pacific trade and make it easier for US workers and companies to compete in Asia.

The deal faces strong opposition from the leading 2016 presidential candidates and other critics, who say it doesn’t do enough to protect US workers from unfair competition.

A key sticking point during Obama’s stay in Vietnam will be human rights. Five Republican senators sent the president a letter on May 20 labeling Vietnam “one of the most repressive regimes in the world” and urging Obama to press Vietnamese leaders to do more to respect freedom of religion and expression and other human rights.

The letter was signed by Sens Marco Rubio of Florida, John Boozman of Arkansas, John Cornyn of Texas, James Lankford of Oklahoma and Bill Cassidy of Louisiana.

He’s already made a historic trip to Cuba and visited Saudi Arabia, Germany and England. He’s due to make a daytrip to Canada next month, attend a NATO summit in Poland in July and expected to become the first president to visit Laos in the fall.