HANOI, Vietnam >> A prominent Vietnamese blogger told an appeal hearing on Thursday that his sentencing earlier this year to five years in prison for anti-state writings was not based on any evidence.

Nguyen Huu Vinh, better known as Anh Ba Sam, was convicted of abusing democratic freedoms to infringe on the interests of the state at a one-day trial in March. His colleague, Nguyen Thi Minh Thuy, who was given a three-year jail term on the same charge, is also appealing her sentence.

At the appeals trial in Hanoi, Vinh maintained his innocence.

“The verdict did not provide any valid evidence to convict me,” Vinh told the court. “In the 24 articles, there was no evidence to demonstrate that I instructed Thuy to post them.”

Vinh, 60, quit the police force and set up a private investigation firm. He then launched the blog Dan Quyen, or Citizens’ Rights, in 2013, and Chep Su Viet, or Writing Vietnamese History, in early 2014. The blogs provided links to news on political, social, economic and cultural issues from state media as well as from activists.

At his trial, prosecutors said the two blogs posted 2,397 articles and generated more than 3.7 million hits, and that 24 of the articles had “untruthful and groundless contents” which tarnished the country’s image.

Vinh’s wife and son were allowed into the court where six lawyers represented Vinh and Thuy. Diplomats and international media were allowed to follow the proceedings in a separate room via closed circuit TV.

International human rights groups and Western governments including the United States have criticized Vietnam for jailing dissidents. Hanoi denies that, saying it only detains those who break the law.

New York-based Human Rights Watch has called for the release of the defendants.

“Vietnamese authorities have decided it is a crime to provide independent information to the Vietnamese public,” Brad Adams, Asia director at Human Rights Watch, said in a statement Tuesday. “The appeals court now has an important opportunity to uphold the right to free speech in Vietnam.”

U.S. officials say Vietnam has made some progress in its human rights record with fewer arrests, but that more needs to be done if it wants to expand bilateral ties.