HANOI (Reuters) - An American detained in Vietnam last month is set to go on trial next Friday, days after U.S. Secretary of State raised the case with local officials during a Hanoi visit.

Will Nguyen, 34, is accused of “causing public disorder”, the Police Department of Ho Chi Minh City said in a statement on its official news website.

Nguyen, of Vietnamese descent, was detained last month following mass protests sparked by concerns that plans to develop economic zones by offering land leases for up to 99 years would be dominated by investors from China, with which Vietnam has a history of fractious ties.

The police statement cited the indictment as saying that Nguyen incited people to protest and tried to overturn a police truck in the city, Vietnam’s economic hub.

His lawyer is not immediately available for comment.

Nguyen’s sister, Victoria Nguyen, said in a letter sent to the Department of State earlier this month that her brother was not violent and was a man of integrity.

“I think we all understand that he is being condemned for something that we all know is our universal birth right: freedom of speech and expression,” Victoria Nguyen said.

U.S. Secretary of State Mike Pompeo raised the issue during his meetings with Vietnamese officials in Hanoi this week, encouraging a speedy resolution.

Police in Vietnam arrested dozens of people following protests by thousands of people in several cities, including a protest in the central province of Binh Thuan that turned violent.

A court in Binh Thuan province on Thursday jailed six people for clashing with police for between two and two and a half years.

According to Vietnam’s penal code, anyone found guilty of causing public disorder may face a prison term of between two and seven years.