On November 15, Vietnam’s security forces detained female activist Dinh Thao upon her landing in Noi Bai International Airport after spending the last four years abroad for international advocacy, Defend the Defenders has learned.

Mrs. Thao who has a 16-month baby returned in her home country from Bangkok where she worked for VOICE (Vietnamese Overseas Initiative for Conscience), a U.S.-based rights group working for promoting human rights and multi-party democracy in Vietnam. She was taken by a group of around ten security officers to a police station for interrogation from the morning of Friday until 5 PM on the same day.

Police confiscated her passport, telling her that they may summon her for further interrogation in the future.

According to VOICE’s press release issued when she was held in police custody, in the past four years, Mrs. Thao has been working to promote human rights in Vietnam by engaging in a number of United Nations (UN)’s human rights mechanisms, advocating the EU and other foreign governments via bilateral agreements with Vietnam.

She has worked closely with international and regional NGOs to enhance knowledge of the international community about Vietnam’s human rights situation, the press release said.

Thao graduated from the prestigious Hanoi Medical University in 2015. She was one of the prominent civil activists in Hanoi before going abroad for human rights advocacy. She was a coordinator of the unregistered environmental group Cây Xanh (Green Trees) during its campaign in 2015 which aims to protest Hanoi’s authorities plan to chop down thousands of aged trees in the capital city’s main streets. She was also among key organizers of a campaign supporting independent candidates for the country’s highest legislative body National Assembly in the general election in 2016.

Thao’s detention was condemned by a number of international rights groups, including Amnesty International and Human Rights Watch.