Lisbon"s mayor apologised on Thursday for what a "bureaucratic error" that led to his city hall sharing with Moscow the contact details of three Russian organisers of a rally in support of jailed Kremlin critic Alexei Navalny. Facing calls from some opposition politicians to resign, Mayor Fernando Medina told reporters: "I apologise to the protest organisers ... and I want to assume (responsibility for) this regrettable mistake that should have not happened." Medina, from Portugal"s governing Socialist Party, ruled out stepping down over the January incident, reported by the Expresso and Observador newspapers on Wednesday night. He said the position of Portugal and the European Union was in line with the views expressed by the protesters. His office said the sharing of such data with embassies facing protests over their countries" policies was city hall"s "normal procedure" until April, when it ceased doing so to protect protesters" rights. Following this procedure in a case where there was a risk for participants was a bureaucratic error, Medina said. The Russian embassy said the incident was "undoubtedly fuelled by the activists" desire to attract media attention to themselves through widespread politicisation and deplorable provocations". "Neither the embassy in Lisbon nor Moscow are interested in such individuals," it said. "We have other priorities." Navalny was arrested in January on his return to Moscow from Germany after being treated for what doctors said was poisoning with a nerve agent. The Kremlin has denied any role in his illness and said it has seen no proof he was poisoned. Navalny was later jailed for parole violations related to an embezzlement case he says was trumped up. read more Activists protested over his arrest in many countries including Portugal, where the mayor"s office approved a rally near the Russian embassy after providing organisers" names. "The Portuguese state did not protect me. I felt betrayed," Ksenia Ashrafullina, who has dual Portuguese and Russian citizenship, told Reuters after her contact details were shared with the Russian embassy and foreign ministry. "After Navalny was poisoned, we realised Russia was becoming more violent towards its citizens so how am I going to be allowed back in? Maybe nothing will happen but there"s no protection any longer."