Three Peoples' Democratic Party (HDP) officials were detained in Turkey on Friday, local media reported, days after the government moved to dissolve the opposition party.

According to state-run Anadolu News Agency, HDP officials in two Istanbul districts were arrested, and police seized “organizational documents and digital materials” in what the news outlet said was an operation targeting the outlawed Kurdistan Workers Party (PKK). The group has waged a decadeslong violent insurgency on Turkish soil and is designated as a terrorist organization by Turkey, the European Union and the United States.

On Wednesday, a Turkish prosecutor filed a case with the Constitutional Court to dissolve the HDP, the country’s second-largest opposition grouping in the parliament. The indictment accuses the HDP of ties to the PKK, a Kurdish militant group that both Turkey and the United States have labeled a terrorist organization.

Both the EU and the United States condemned the move, with the US State Department warning the HDP’s dismantling would “further undermine democracy  in Turkey.”