The head of Catalonia's regional government on Thursday denied having links to seven separatist activists jailed in September on suspicion of belonging to a "terrorist" group that planned to occupy the Spanish region's parliament.

Prime Minister Pedro Sanchez, who is facing a general election on Sunday, had demanded that Catalan president Quim Torra explain after local media reported that members of the group had told investigators that the order to occupy the assembly came directly from Torra.

According to transcripts of tapped phone conversations included in court documents seen by AFP, two of the jailed activists discussed a plan to occupy Catalonia's regional parliament in Barcelona with "the Catalan government inside" and "resist during one week".

In the recorded conversations, one of the suspected leaders of the group implicated Torra and his predecessor Carles Puigdemont, who is currently in Belgium, calling them by the code names "Gandalf" and "Lisa".

In a video of his interrogation by police which was leaked to the media, the man also said that the plan "came from the presidency... from Torra".

Catalonia's regional government said in a statement that Torra "denies" the reports which lacked "any type of credibility".

"Moreover, he maintains he never had any type of relationship with the detained," the statement added.

Protests have mounted since the Supreme Court jailed nine Catalan leaders last month
Protests have mounted since the Supreme Court jailed nine Catalan leaders last month AFP / LLUIS GENE

Spain's Guardia Civil police force suspects the activists had planned to occupy the Catalan parliament after Spain's Supreme Court on October 14 sentenced nine Catalan separatist leaders to jail terms of up to 13 years, prompting days of angry street protests.

Police in September arrested nine separatists, accusing them of belonging to a new and unknown group, the Tactical Response Team.

Spain's top criminal court, which had ordered the investigation into the group, ordered that seven of them to be held in jail while the probe continues.

The court suspects the group allegedly intended to use "any means, including violent ones" to establish an independent republic and possessed materials that could be used to make explosives.

The group's lawyer Xavi Pellicer said "the accusations of terrorism do not hold up by any means" and that the case was part of a "politically motivated" attempt to criminalise the Catalan independence movement.

He also said the suspects made their statements to police following "threats and coercion".