Spanish police have blocked off more than half of the designated polling places ahead of Sunday’s vote, officials say. Groups of activists are camping out at schools across the region and insist the vote will go ahead.

he Spanish government said on Saturday that families were occupying 163 schools in Catalonia and added that 1,300 of 2,315 designated voting stations have been sealed off by police.

Supporters of Catalan independence on Friday evening and Saturday morning occupied polling stations, setting the scene for possible confrontations with police.

Spanish Foreign Minister Alfonso Dastis called Catalonia plan to hold an independence referendum is “a mockery of democracy.”

Catalonia’s government said it had set up hundreds of polling stations across the northeastern region ahead of Sunday’s vote, despite Madrid declaring the vote illegal.

“Everything is prepared at the more than 2,000 voting points so they have ballot boxes and voting slips, and have everything people need to express their opinion,” Catalan leader Carles Puigdemont told Reuters news agency on Friday.

Spain’s central government, bolstered by a Constitutional Court ruling declaring the referendum invalid, has vowed to block the unauthorized poll.

“I insist that there will be no referendum on Oct. 1,” central government spokesman Inigo Mendez de Vigo told a news conference Friday. “Nobody is above the law and whoever violates them will face consequences.”

Spain’s constitution stipulates that only the federal government has the power to call a referendum on sovereignty.