Police in the north-central province of Ha Tinh have arrested a female activist as the authorities continue their campaign to silence opposition voices.
A police statement said that Tran Thi Xuan was being investigated on a charge of attempting to overthrow the people’s administration under Article 79 of the penal code.
The 41 year old is not well known in other parts of the country, but is reported to have been involved in a campaign led by Catholic priests over an environmental disaster that hit the central coast in 2016.
The priests helped organise mass protests along the affected coastline, demanding compensation and accountability following a toxic leak from the Formosa steel plant in the province that destroyed fish stocks.
The police allowed some protests in the months following the disaster, but later moved to break up demonstrations. State media warned earlier this year that the organisers could face criminal charges amid signs that the authorities were alarmed at the scale of the protests and the degree of organisation.
The details of the charges against Ms Xuan were not made clear in a statement released by Ha Tinh police.
Article 79 is one of the toughest laws used by the authorities to crack down on dissent.
It has been employed more frequently in recent months, notably following the arrest in July of four members of the Brotherhood for Democracy, a civil society group that advocates for more pluralistic government.
Those convicted under the article could face the death penalty, although most in recent years have been sentenced to long prison terms.