Catalan government computer systems were attacked by professional-style hackers during the disputed independence vote on Nov. 9, putting basic services at risk, Regional President Artur Mas said.

The attacks began the day before the ballot and peaked as 2.3 million Catalans went to the polls, with information requests to regional-government computers increasing 60,000- fold, Mas said at a press conference in Barcelona today. The attacks put emergency services and the the delivery of medical prescriptions at risk, he said.

“We’ve never suffered such a big attack,” Mas said today. “We suspect this wasn’t the action of a few amateur hackers.”

Eighty-one percent supported a full split from Spain in the ballot and about 37 percent of potential voters turned out, adding to pressure for Spain’s Prime Minister Mariano Rajoy to engage with Mas. The Catalan leader went ahead with the vote in the face of a Constitutional-Court ban and ignoring prosecutors’ orders to the regional police to identify the public officials who facilitated the vote.

The ballot marks the highest point so far in a four-year resurgence of separatist sentiment which has put Rajoy on the defensive as he struggles to maintain the support of voters amid a raft of corruption allegations and the harshest budget cuts in a generation. Rajoy had said for the past year the vote wouldn’t happen because it breached the constitution.

Mas plans to open negotiations with other parties calling for a formal, binding vote on independence before deciding on his next move. Mas has written to Rajoy asking him to discuss the conditions for a referendum, he said. The regional elections could be used as a de facto referendum if Rajoy refuses to budge, he added.

“It’s not about doing elections for their own sake, it’s a question of how do we hold a definitive consultation,” said Mas. “Elections are just the tool for doing this consultation.”