Brazilian President Michel Temer attends the ceremony of 152th anniversary of the Riachuelo Naval Battle at the Marine Corps Headquarters in Brasilia, Brazil June 9, 2017. REUTERS/Ueslei Marcelino

SAO PAULO (Reuters) - Brazil’s Supreme Federal Court urged a thorough investigation into reports that the country’s secret security service spied on Justice Edson Fachin, in the latest clash involving President Michel Temer’s embattled administration.

Court president Carmen Lúcia said in a statement on Saturday that, if proved accurate, such reports show an inadmissible meddling into the court and an attack against democratic liberties in Latin America’s biggest country.

Magazine Veja reported late on Friday that the agency known as Abin might have been used to spy on Fachin - the top court justice in charge of a massive corruption probe that has ensnared Temer.

Temer’s office denied the Veja report, saying the Abin “acts in accordance with the purpose for which it has been created”.

If the report proves accurate, Lúcia said in the statement, punishment of the alleged espionage should take into account the grave “legal, political and institutional consequences of such an act.”

“Common in dictatorships, these practices ... are serious and, when carried out against a judge, are completely unacceptable in a democracy,” Lúcia said in the statement. “It has to be probed and repudiated, and any responsible parties properly punished.”

Her remarks add to tension between the executive and judiciary branches of power, which gained intensity in the wake of Fachin’s decision to validate a plea deal involving Temer in a corruption probe. Prosecutors allege that Temer worked to obstruct justice and condoned efforts to pay for the silence of a potential witness.