MADRID (AP) — Spain's National Court is to quiz two senior officers of Catalonia's regional police force and the leaders of two pro-Catalan independence civic groups who have been placed under investigation for sedition.

The court said Wednesday the four will be questioned on Friday about their roles in demonstrations Sept. 21-22 in Barcelona when Spanish police arrested several Catalan government officials and raided offices in a crackdown on preparations for last weekend's referendum on Catalonia's independence.

Spanish authorities say the demonstrations hindered the police operation. During the rallies, there were some disturbances and two police vehicles were thrashed.

The four include regional police chief officer Josep Lluis Trapero and Jordi Sanchez, the head of the Catalan National Assembly that has been the main civic group behind the independence movement.