ATHENS, Greece (AP) — Greek authorities have launched a major search operation on the Aegean island of Ikaria for a British woman reported missing after she went for a morning run and failed to return.

Police said Tuesday that police, firefighters, the coast guard and volunteers were participating in the search for the 35-year-old woman, whom they did not publicly identify. A helicopter was also to participate in the search. Police said they were keeping all lines of inquiry open.

Local media identified the woman as Natalie Christopher, an astrophysicist who lives in Cyprus and who was reported missing by her partner, with whom she was vacationing on the island.