TBILISI, Georgia (AP) — Georgian police on Wednesday raided the offices of an opposition party and arrested its leader in an apparent attempt to squelch a wave of mass protests triggered by the governing party’s decision to suspend negotiations on joining the European Union.

During the past six nights, riot police used water cannons and tear gas to disperse the demonstrators, who threw fireworks at police officers and built barricades on the Georgian capital’s central boulevard. More than 300 protesters have been detained since Thursday and over 100 people have been treated for injuries.

On Wednesday, the Coalition for Change opposition party said that police raided its offices and detained its leader, Nika Gvaramia. It shared a video showing several officers dragging Gvaramia into a car.

Georgian media reported that police also raided the offices of several other opposition groups and non-government organizations.

Prime Minister Irakli Kobakhidze of the Georgian Dream party said the raids targeted those who encouraged violence during protests in an attempt to topple his government. “I wouldn’t call this repression; it is more of a preventive measure than repression,” he said.

The ruling Georgian Dream retained control of parliament in the disputed Oct. 26 election, which was widely seen as a referendum on Georgia’s EU aspirations. The opposition and the pro-Western president have accused the governing party of rigging the vote with neighboring Russia’s help and boycotted parliament sessions.