BERLIN (AP) — The German government said Wednesday that it is concerned by the recent detention of a prominent environmental campaigner in Vietnam, warning that a recent multi-billion-dollar deal to help the country phase out coal use requires the involvement of civil society activists.

Hoang Thi Minh Hong was detained by police in Ho Chi Minh City last week and held on a temporary order charged with tax evasion, the United Nations Human Rights Office said, citing credible sources. It said Hoang is the fifth prominent environmental activist arrested in Vietnam for alleged tax evasion in the last two years.

Germany's Foreign Ministry said the arrests of Hoang and others “are an alarming signal for civil society actors across the country, as well as for environmental and climate protection.”

“We also view the arrest critically with regard to the upcoming implementation of the Just Energy Transition Partnership (JETP) agreed between Vietnam and the G7 countries, Denmark and Norway,” it said.

The deal agreed at the end of 2022 saw the two Nordic nations and the Group of Seven rich industrialized countries pledge $15.5 billion to help Vietnam accelerate its shift from coal power to renewable energy.

The deal is meant to help the Southeast Asian country reduce its emissions to “net zero” by 2050, a goal which expert say needs to be met globally to cap global warming at 1.5 degrees Celsius (2.7 degrees Fahrenheit).

It is one of several agreements that developing and rich nations are negotiating to meet global climate goals. The first such deal was signed with South Africa in 2021, and a similar agreement was reached with Indonesia last year.

The Foreign Ministry said the involvement of civil society in the process was “explicitly anchored in the agreement with Vietnam at the behest of the German government.”

“Climate and environmental protectors such as Hoang Thi Minh Hong play an indispensable role,” it said.

Germany has itself come under criticism for recent police raids on climate activists who have regularly disrupted traffic across the country.