Following a police investigation, prosecutors have declared Transparency International Russia to be a “foreign agent,” obligating the NGO’s Russia office to register specially with the Justice Ministry.

Elena Panfilova, the chairperson of Transparency International’s Russian branch, announced the news today, vowing to challenge the decision in court.

According to Panfilova, prosecutors determined that Transparency International engages in political activity and receives foreign funding. “We’re opposed to the entire concept here,” Panfilova said.

“Regarding foreign funding, we’ve never hidden the fact that we’re part of an international movement, and a portion of our funding comes from our global front office. That’s how it’s always been and how it always will be,” Panfilova insisted.

The public first learned about the investigation into Transparency International Russia in late January 2015, when it was also announced that police are probing several other prominent human rights organizations, including the Moscow Helsinki Group and Civic Assistance Committee.

Transparency International is an NGO that monitors and publicizes corporate and political corruption. The organization is famous for its annual Corruption Perceptions Index, which “scores countries on how corrupt their public sectors are seen to be.” The organization was founded in 1993, and currently has branches in more than 100 countries.

Russia’s law on foreign agents was adopted in 2012. It requires NGOs engaged in political activity and receiving foreign funding to register with the Justice Ministry as “foreign agents” and adhere to stricter government oversight. The Justice Ministry is also empowered to force NGOs to register on this list, when they refuse to do so voluntarily. Organizations designated as foreign agents that refuse to register with the Justice Ministry are subject to fines.