MADRID (REUTERS) - Spain's government on Tuesday (April 19) denied illegally spying on Catalan independence leaders but was mum on whether it had undertaken any court-approved electronic surveillance after a rights group found that dozens of separatists' phones were targeted.

On Monday, Canada's Citizen Lab group said that in the wake of a failed independence bid in 2017, more than 60 people linked to the Catalan separatist movement, including current and former regional leaders, had been targets of "Pegasus" spyware made by Israel's NSO Group.

"The government has nothing to hide," spokesperson Isabel Rodriguez said after a weekly cabinet meeting on Tuesday, adding that the Madrid government would cooperate fully with any investigation into the allegations.

"Spain is a democratic state with full rule of law and any curtailing of fundamental rights requires an injunction or a court order," Rodriguez told reporters.

Citizen Lab said it could not directly attribute the spying operations but that circumstantial evidence pointed to Spanish authorities.

Asked if Spain had ever engaged in legally-sanctioned electronic surveillance of Catalan leaders or if Madrid had access to Pegasus, which can be used to remotely break into iPhones, Rodriguez declined to answer directly.

"There are subjects that, because they involve national security, are protected by law, and classified, secret matters that I cannot tell you about," she said.

Citizen Lab is known as one of the leading research groups on mercenary spyware within the cybersecurity industry.

It also revealed this week that it had warned British officials that electronic devices connected to government networks, including in the prime minister's office and foreign ministry, appeared to be targeted with Pegasus.

The group began its Spanish inquiry in 2020 after researchers working with Facebook's instant message service WhatsApp warned several Catalan lawmakers, including former parliamentary speaker Roger Torrent, that their phones had been hacked.

At that time, a Barcelona court opened an investigation after Torrent and another member of parliament filed a lawsuit against the Spanish government.

El Pais newspaper reported on Tuesday that the investigation had been stalled for over a year as the court was awaiting a response from the Israeli government.