When Vietnam was awarded a multibillion-dollar deal by a group of nine wealthy nations last year to work on reducing its use of coal, it agreed to regularly consult with nongovernmental organizations.

Instead, the government has arrested several prominent environmentalists from those organizations who shaped policies that helped secure the funding, prompting concerns over sending money to countries that have violated human rights.

As the country prepares to announce how it will spend the money at the United Nations climate talks that begin Thursday, activists are saying that Vietnamese officials need to be held accountable for what they are calling a harsh crackdown against those who speak out about the country’s environmental woes.