[Leftist demonstrators march in protest against the visit of US President Barack Obama in Athens, Tuesday, Nov. 15, 2016. Obama is in Athens for talks with the country's political leadership and is scheduled to deliver a speech on Wednesday before heading to Berlin later the same day as part of his last major trip abroad. (AP Photo/Thanassis Stavrakis)]ATHENS, Greece (AP) — Greek police say about 3,000 anarchists, left-wing group supporters and students are marching through central Athens, to protest President Barack Obama's visit.